Category: U.S. Congressional Elections 2016

Which party will control the US Senate after the November 2016 election? (update)

According to Slate, “Choosing [Senator Elizabeth] Warren would be an uncharacteristically bold and thrilling move for the cautious Clinton, one that would help unite Sanders supporters behind her candidacy while throwing its feminist promise into high relief”[1].

I think it is unlikely that HRC would choose Sen. Warren as her running mate, but notice that if she did, and the Clinton/Warren ticket won the White House, there would be consequences for control of the Senate. Massachusetts has a Republican Governor who would, presumably, choose a fellow Republican to replace Sen. Warren in the upper chamber. True, an election for a replacement would follow in 145-160 days[2]. But there’s no guarantee that the electorate would return a Democrat. As recently as 2010, Republican Scott Brown was elected to the Senate by the voters of the mayflower state. That fact alone might be a deal-breaker for a Clinton/Warren ticket. But if it’s not, control of the Senate might be even harder to predict.



Will a new Supreme Court Justice be appointed before 20 January 2017? (update)

Haven’t thought much about this lately, so it looks like it’s time for an update.

Politico tells us that “Democrats are getting badly outspent by their conservative rivals in the war over Merrick Garland’s confirmation, suggesting that President Barack Obama’s closest allies in the Supreme Court battle have more bark than bite…The muscular spending from GOP-backed groups shows how dug-in conservatives are over their Garland blockade, and has helped keep almost all Senate Republicans moving in lockstep”[1]. Sounds bad for the Ds. But does money matter here? I can’t quite see how the mechanism is supposed to work (or, more exactly, work well).

More important, I think is the near inevitability of Mr. Drumpf’s nomination[2] and his less than stelar chances in the general election[3]. These facts might throw a spanner into the works. R Senators could be willing to make their peace with the Garland nomination in order to avoid getting a nominee to his left after HRC enters office. Yet the Senators probably needn’t be in a rush. If HRC wins, they could approve Mr. Garland after the election[4][5].

Now here’s an interesting wrinkle: Some folks on the right even fear what will happen if Mr. Drumpf is elected: “If Drumpf has a choice between an originalist conservative with sterling credentials who would often block Drumpf, and buddy of his who hasn’t read the Constitution but would let Drumpf do what he wants, who do you think Drumpf would pick?”[6]. Mr Drumpf has repeatedly promised to provide a list of possible nominees, but he hasn’t delivered yet[7]. Maybe it’s just as well; his mercurial nature would render such a list out-of-date before we ever saw it.

So if HRC wins, then approve Mr. Garland after the election, and if Mr. Drumpf wins, then approve Mr. Garland after the election. Therefore, approve Mr. Garland after the election? Well, maybe. Here are some things that might, just might, stand in the way:

  • (a) HRC wins, but President Obama withdraws Mr. Garland’s name in deference to the incoming president.
  • (b) HRC wins, but Senate Rs can’t get their act together to approve Mr. Garland during the lame duck session.
  • (c) HRC wins, and Senate Ds think they can do better than Mr. Garland.
  • (d) Mr. Drumpf wins, and Senate Rs think they can do better than Mr. Garland.
  • (e) That thing I said before about another Supreme Court Justice dying might happen
  • (f) Something I haven’t thought of yet.

While (a) could happen[8], I don’t know of any evidence that President Obama is actually considering this possibility. HRC has said, if she wins the election, she won’t ask Mr. Obama do withdraw Mr. Garland’s nomination[9]. While she could easily reverse course on this point, I’m not sure she’d have that much to gain by doing so. On the contrary, if the Senate confirms Mr. Garland after the presidential election, she’ll have one less fight with the Senate on her hands. Low probability – call it 10%.

I think (b) is more likely[10]. In order for the Senate to confirm Mr. Garland, Sen. Grassley would have to relent and somehow find a way to save face after repeatedly saying “No way, Jose”[11]. But Sen. Cruz’s remarkably fast climbdown from “We’re in it to win it” to “Sayonara, suckers” is a reminder that a post-haste volte-face that seemed unlikely can happen when conditions change. In addition to Sen. Grassley’s embrace of pretzel logic, there would have to be enough Sen. Rs and Ds who are in the mood to give the Garland nomination priority. That’s not a given. Surely, some departing R senators will have some last minute business to attend to, and that might soak up whatever time is available to deal with Mr. Garland’s nomination. And voters are less interested in this sort of thing than I used to think[12]. From a distance Senate Rs might look like a unified bunch, but they have some sharply divergent interests, and that might keep them from doing what might be in all of their interests. Fairly probable – call it 30%.

I love (c), but I think it’s pretty damn unlikely. Strictly speaking, the Rs would need only 6 Ds in order to confirm Mr. Garland. Even if they had a lot of R defections, I feel pretty confident that they could scrounge up 15-20 Ds. Only a D filibuster could stop the process, and that’s the last card that Ds would want to play in these circumstances (assuming that an HRC victory brings with it control of the Senate). Very low probability – call it 1%.

As for (d), I’ve already mentioned grumblings among the Rs that Mr. Drumpf would unlikely to provide a candidate who is, all things considered, superior to Mr. Garland. Thing is, those grumblings aren’t, to the best of my knowledge, coming from Senate Rs. On the contrary, Sen. Chuck Grassley has said that “there’s no problem with” Mr. Drumpf “appointing people to the Supreme Court”[13]. Low probability – call it 5%.

I’d say (e) is still pretty damn unlikely but interesting nonetheless[14]. Very low probability – call it 1%.

And (f)? Well, I could use some help, and I’ll reevaluate as soon as I get some.

Since I currently think HRC is a 71/29 favorite over Mr. Drumpf[15], I must think that the odds that Mr. Garland will be appointed are something like this: (0.71*.59) + (0.29*0.06) = 0.43. That’s certainly a higher probability than I had earlier thought, largely because of the Ds increased probability of taking the White House.






[6] Quoted at











Which party will control the US House of Representatives after the November 2016 election?

It’s unlikely that the Ds will take back the House, but the question, of course, is how unlikely? Here’s a stab at answering that question.

First, the basics: There are 435 Congressional seats with voting rights, though 1 of these seats is currently empty. There are also 6 seats (from the U.S. territories, commonwealths, and the District of Columbia) without voting rights. Since the question is about control over the House, I’ll ignore the seats without voting rights. (Sorry, folks. You really should have voting rights, but I can’t fix that here.) So, in lieu of further vacancies, a party needs at least 218 seats to control the House. (I ignore here the complications raised by the election of third-party candidates, as this is unlikely to be relevant in 2016.) At the moment, the Rs have 246 seats, and the Ds have 188. So the Ds would have to win a net of 30 seats from the Rs to gain control of the House.

That’s a lot of seats! But it’s not like we’ve never seen such a thing. As recently as 2010, Rs picked up 63 seats in a single election cycle. A smart thing to do would be to look through all of the recent elections, and see what the average amount of change has been. But I’ve been struggling to find these data in a digestible form[1]. I ended up working with a data set that had the virtue of going back to the beginning of our Republic but which also had a number of annoying typos in it[2], which I think I’ve managed to correct. I limited my number crunching to all of the elections following 1921, the first year in which the number of Congressional Representatives was fixed at 435. In the average House election (whatever that means), Ds lose 2 seats, and Rs pick up 2.33. Why aren’t these numbers symmetrical, you ask? Third-party candidates. More importantly, there’s is a ton of variance. The standard deviation for the Ds is 36.23 and for the R is 37.07. On no less than 18 occasions (out of 51 possibilities), one party picked up at least 30 seats.

  1. 1914 election: R Pres (Taft) in office during election, Rs pick up 66 seats
  2. 1920 election: D Pres (Wilson) in office during election, Ds lose 59 seats
  3. 1922 election: R Pres (Harding) in office during election, Rs lose 75 seats
  4. 1928 election: R Pres (Harding) in office during election, Rs pick up 30 seats
  5. 1930 election: R Pres (Hoover) in office during election, Rs lose 53 seats
  6. 1932 election: R Pres (Hoover) in office during election, Rs lose 101 seats
  7. 1938 election: D Pres (Roosevelt) in office during election, Ds lose 71 seats
  8. 1942 election: D Pres (Roosevelt) in office during election, Ds lose 45 seats
  9. 1946 election: D Pres (Truman) in office during election, Ds lose 55 seats
  10. 1948 election: D Pres (Truman) in office during election, Ds pick up 75 seats
  11. 1958 election: R Pres (Ike) in office during election, Rs lose 48 seats
  12. 1964 election: D Pres (LBJ) in office during election, Ds pick up 36 seats
  13. 1966 election: D Pres (LBJ) in office during election, Ds lose 47 seats
  14. 1974 election: R Pres (Ford) in office during election, Rs lose 48 seats
  15. 1980 election: D Pres (Carter) in office during election, Ds lose 36 seats
  16. 1994 election: D Pres (Clinton) in office during election, Ds lose 54 seats
  17. 2006 election: R Pres (Bush II) in office during election, Rs lose 33 seats
  18. 2010 election: D Pres (Obama) in office during election, Ds lose 63 seats

Bad news for the Ds: The majority (78%) of the time, the party that loses 30 or more seats in the House is the party with the sitting president at the time of the election. Worse news for Ds: The party with a sitting president loses on average 13.3 seats per House election. Slightly better news for the Ds: Given the high level of variance, there is a 0.123 probability of picking up 30 or more seats if your party holds the White House. (I haven’t shown my work here because it was tedious to do and, I reckon, would be even more so to look at.)

So far, so good. But foxes are supposed to have more than one trick up their furry little sleeves. So let’s try it from another angle. According to the Cook Political Report, there are 65 district races that are to at least some degree competitive[3]. 19 of these are currently held by Ds, and the remaining 46 are held by Rs. That leaves 169 safe seats for the Ds and 200 safe seats for the Rs. The question, then, is this: How likely is it that the Ds can win 49 of the 65 (or more) of the competitive seat?[4]

Glad you asked. CPR ranks these races as Solid R, Likely R, Leans R, Tossup, Leans D, Likely D, and Solid D. On the basis of CPR’s own assessment of their levels of accuracy[5] and a little bit of body English, I’m translating these qualitative judgments into quantitative judgments as follows:

  • Solid R: 0.997 probability of an R victory, 0.003 probability of a D victory
  • Likely R: 0.95 probability of an R victory, 0.05 probability of a D victory
  • Leans R: 0.85 probability of an R victory, 0.15 probability of a D victory
  • Tossup: 0.50 probability of an R victory, 0.50 probability of a D victory
  • Leans D: 0.15 probability of an R victory, 0.85 probability of a D victory
  • Likely D: 0.05 probability of an R victory, 0.95 probability of a D victory
  • Solid D: 0.003 probability of an R victory, 0.997 probability of a D victory

The average expected outcome is that Ds win 29 (rounding up from 28.79) of the 65 contested seats. That gets them to 197 total seats in the House, a nice outcome with their party holding the White House but far short of a majority. I ran a 1,000 round Monte Carlo simulation, and not once did Ds win more than 40 of these 65 seats (though they did hit 39 on a few occasions). Since Ds need to win 49 of the 65 competitive seats to take control of the House, I’m pretty damn pessimistic about their chances.

“Unless…unless it’s 1964 all over again,” you might say. As we saw above, in 1964 LBJ ran as an unelected incumbent against an extremely unpopular R candidate, Barry Goldwater, who won the nomination after a highly contentious convention. Sound familiar? LBJ won the presidency in a landslide, and the Ds netted themselves 36 seats, 6 more than they need in 2016[6].

But I’d urge caution about betting the farm on another 1964. Marx’s line about history repeating itself “the first time as tragedy, the second time as farce” has to be taken with a grain of salt. He was, after all, referring to “all great world-historic facts and personages”[7]. Honestly I don’t think either Barry Goldwater or Donald Trump count as great world-historic personages, and I don’t their runs for office are great world-historic facts. And Marx was at a point in his career where the pithy phrase was sometimes more important than the carefully reasoned analysis.

Anyway, it’s unwise to become fixated on a single data point when so much data is available. In 2003, we were obsessed with Munich, and anyone who voiced doubts about going to war with Iraq was an Attlee-esque appeaser, never mind the many, many dis-analogies. Sure, Mr. Trump could bomb as a general election candidate and drag down a lot of R House Representatives with him; I don’t deny that for a second. But Rs running for House seats have been running away from Mr. Trump for some time now[8], and there are reports that the Koch brothers are shifting their considerable financial resources away from the presidential race (where they don’t like what’s on the menu) to Congressional and state-level races[9] where money makes a bigger difference. If we can see the risk to Rs in the House, it’s no surprise that they can too and that they’re acting tactically to try to counter the risk.

TL;DR: The historical data suggests something like a 12% chance that the Ds will retake the House, while the race-by-race data suggests a lot less, probably less than 1%. I’ll blend these odds a nock it up 3% because treating the House races as if they were independent from one another (or, more properly, as if they were independent of common factors like who’s at the top of the ticket) is obviously inadequate. So, for the moment at least, the Ds have a 10% of taking the House, while the Rs have a 90% of keeping it.

[1] Brookings has the numbers since 1946, but they’re in PDF format and not easily importable to a spreadsheet:–Congressional-Elections.pdf



[4] That is to say, they need to win 19 of the 65 to break even and another 30 of the remaining 46 to take control.


[6] Suggested in, for example,

[7]  Karl Marx (1952) “The Eighteenth Brumaire of Louis Napoleon,” quoted from


[9] Somewhere in a New Yorker interview with Jane Mayer that I can’t find at the moment.

Which party will control the US Senate after the November 2016 election?

Since this is my initial forecast, I’ll just try to develop a reasonable prior. Here’s what I think; why I think it follows:

  • Republican retain control of Congress with 51+ Congressional seats: 0.42
  • Democrats seize control of Congress with 51+ Congressional seats: 0.24
  • Republicans and Democrats each have 50 Congressional seats: 0.34

Here are the basic facts (which you can skip if you’re already in-the-know): There are 34 seats are up for re-election. 24 are currently held by Republicans, and 10 are held by Democrats. Since there are 54 Republicans in the Senate now, that means that the Republicans can count on a bare minimum of 30 seats after the election, and the Democrats can count on a bare minimum of 36 seats. (I’m counting the 2 independents who caucus with the Democrats as Democrats for now, but I’ll revisit this point later.)  17 of the seats up for election are functionally out of play. 10 of these are held by Republicans, so they can really count on 40 seats after the election. The other 7 are held by Democrats, so their floor is really 43 seats. Of the 17 seats that are competitive to one degree or another, 14 of these competitive seats are currently held by Republicans and 3 are held by Democrats.

So much for the basic facts. It would be nice to have some sense of how likely it is that a Democrat or a Republican will win each of these 17 competitive elections.  And Wikipedia (of all places!) provides some raw useful information to this end[a]:


The final four columns of this table list estimates of how likely each of these Senatorial seats is to go to either a Republican or a Democrat. The estimates come from the Cook Report, the University of Virginia Center for Politics, Roll Call, and the Daily Kos. Since these are qualitative assessments, and we need quantitative assessments, I (somewhat arbitrarily) came up with the following cypher:

  • Safe D = 0.90 probability of D victory
  • Likely D = 0.75 probability of D victory
  • Lean D/Tilt D = 0.60 probability of D victory
  • Tossup = just what it sounds like, 0.50 probability of D victory




And, of course, I did the same for Republicans. I’m certainly open to better translation of the qualitative assessments into quantitative assessments, but this seems like a reasonable place to start.

My next step was to average the four quantitative assessments. While I didn’t weight any of the sources of these assessments, I was tempted to give the Cook Report added weight because of its reputation for accuracy[b]. Again, I’m open to better approaches. Next, I determined the mean, median, and standard deviation of the average assessments. Here’s what that looks like:


Hence, for any given competitive Senate seat, the expected value to the Republicans is 0.61, and the expected value to the Democrats is 0.39. And the most likely outcome is that Republican end up with 50.5 Senate seats, while Democrats get 49.5. Of course, there’s a small problem here – namely, that actual Senate seats come in discrete quantities along the lines of the positive integers. No one is going to end up with 0.583774 of a Senate seat any time soon!

But the magic of numbers[c] comes to the rescue again. We know that in order to retain their majority in the Senate, Republicans will need to win 11 of the 17 seats up for grabs in these competitive races, since they have a floor of 40 seats. And 11/17 = 0.65, rounding up a bit. Furthermore, we know that the standard deviation for the data series I mentioned is 0.20[d], which you can take my word for if you don’t want to do your own calculation. Given this data, there’s a 0.4207 (call it 0.42) probability that the Republicans will retain 51 or more Senate seats in this election cycle. Contrariwise, Democrats need 8 of the 17 Senate seats, since they have a floor of 43 seats. And 8/17 is about 0.47. Given all of the data we have, we can estimate a 0.242 probability of that happening. 

But here’s the thing. Eagle-eyed readers will surely have noted that 0.4207 (the probability of Republicans retaining control of the Senate) + 0.242 (the probability of the Democrats seizing control of the Senate) does not equal 1. That’s because there’s a rather remarkable 0.3373 probability that we’ll see 50 Republicans and 50 Democrats in the Senate, according to the (admittedly overly) simple model I’ve pieced together! That’s a big surprise to me.

Here are 2 take aways from this fact: To start with, GJ needs to step up and tell us how they mean to score this event if there’s a 50/50 split in the Senate. For practical purposes, of course, control will rest in the hands of the party that has the tie-breaking vote, and that will be whichever party wins the presidential election. If that’s what GJ has in mind, I hope they’ll say so soon (and I apologize if they’ve already done so, but I’ve missed it). Furthermore, if the importance of the presidential election didn’t seem clear enough to me before, it certainly does now. The outcome of the presidential election has a more than 1-in-3 chance of determining which party has control of the Senate. That’s huge. The upshot for the time being: I’m going to assign each party half of the value of 0.3373, but that’s just a temporary fix.

Four more points need to be made: First, the two independents in the Senate are Angus King (ME) and Bernie Sanders (VT). Both Sen. King and Sen. Sanders caucus as Democrats. Hell, Sen. Sanders is running to be the Democratic nominee for president in 2016. So it’s pretty safe to think of them as Democrats, though it would be very nice to have confirmation from the GJ judges on this point. By the way, neither Sen. King nor Sen. Sanders is up for reelection this year, as they are both Class 1 Senators.

Second, I haven’t tried to use any historical data to help guide my forecasting, and that worries me. I believe that there’s a rough-and-ready tendency for the party who has a two-term president completing his time in office to lose Senate seats[e]. But I need to do more homework on this before I try to upgrade my little toy of a model.

Third, I’ve treated the Senate elections as if they were independent variables. That’s something of a fiction. Senate elections are likely to be deeply influenced by the presidential election, and there’s long been speculation that a Trump candidacy could be a disaster for Republicans in Congress[f]. But this election cycle has been pretty damn hard to predict. (The good news: It’s not boring. The bad news: It’s not boring.) So I’m going to put a pin in this until there’s enough solid empirical data to use. (And, for Pete’s sake, please tell me if there is, and I’m not in the loop.)

Fourth and finally, all of this bean counting gets scrambled if a Senator dies or has to leave office. “The U.S. Constitution grants the state legislatures the power to determine how U.S. Senators are to be replaced, including empowering the chief executive (the governor) do make these appointments”[g]. Since Republican governors outnumber Democratic governors more than 3-to-2[h], and Republicans control a little more than twice as many State legislatures as Democrats[i]. So Republicans have a huge advantage – an advantage I don’t yet have a way of incorporating into my forecast.





[d] Our old friend Andrey Kolmogorov reminds us that all probability values fall between 0 and 1, inclusive[c]. So we need to be a bit careful about using the standard deviation here. If we has a perfectly normal distribution, then 0.025 of the data would sit north of 1.0, while about 0.0011 would be south of 0. I’ll just fix that on the fly.


[f] For example,