The Republican Party is very, very unpopular and has been so for quite some time. It has a net favorable rating of -29% and has not had a net positive favorable rating since 2005. Currently, we’re currently looking at a 20-year low in the party’s popularity.
Ouch. In contrast, the Democratic Party has a net favorable rating of -1.3%. That’s nothing to write home about, but it’s 22 times better than the Rs.
Will any of this make a difference come November? Less than you might expect. Here are a few data points, going back to 1992 (the first year for which I could find information). I note at the outset that we need to be careful about overgeneralizing, of course.
- 1992: Rs = -3 and Ds = +28, Ds win
- 1996: Rs = +8 and Ds = +2, Ds win
- 2000: Rs = +10 and Ds = +22, Rs win
- 2004: Rs = +11 and Ds = +19, Rs win
- 2008: Rs = -10 and Ds = +24, Ds win
- 2012: Rs = -8 and Ds = +13, Ds win
Begin by noting that there’s not much correlation between the party’s approval rating and the victory of the party’s candidate. The candidate from the party with the higher approval rating won in 1992, 2008, and 2012, and the candidate from the party with the lower approval rating won in 1996, 2000, and 2004. The winning candidate’s party has an approval rating of an average of no more than a 4 percentage points higher than its rival.
That said, a few points stand out. No candidate from a party with a net negative favorability rating has won the White House since Ronald Reagan was in office. Now, it’s possible to make too much of this because *both* parties regularly had positive favorable ratings until pretty recently. Of course, if neither party improves its favorability ratings in the next 5 months, that streak is going to come to an end in 2016. Currently the approval ratings gap is 27 points. In fact, the last time the Republicans won the White House (i.e., 2004), their net favorability rating was 11%, a whopping 40 percentage points higher than their current status.
At the risk of excessive curve fitting, let’s give a further tweak to the data. I’ll add the incumbent’s approval rating to his party’s rating. Here’s the result:
- 1992: Rs + GHWB = -30 and Ds = +28, Ds win
- 1996: Rs = +8 and Ds + WJC= +26, Ds win
- 2000: Rs = +10 and Ds + WJC = +52, Rs win
- 2004: Rs + GWB = +18 and Ds = +19, Rs win
- 2008: Rs+ GWB = -52 and Ds = +24, Ds win
- 2012: Rs = -8 and Ds + BHO = +19, Ds win
That’s a little closer to the historical facts of the last few decades. On average,the winning candidate’s party has an approval rating of an average of a 22.67 percentage points higher than its rival. But the variance is huge: 42 percentage points!
So what does all of this mean for 2016? First, we’d be very unwise to put much stock in the fact that the Democratic Party and its President are much more approved of than the Republican Party. The sum of the net approval ratings for President Obama and the Democratic Party is about 3%, and that’s a lot higher than the Republican Party’s approval rating of -27%. But, first, the Republicans were able to overcome a 42%(!) gap in 2000, coincidentally(?) the last time the Democrats had a sitting president who was not running for the highest office in the land. (Honesty, how the hell to Mr. Bush get elected in 2000? A better question is how the hell Mr. Gore did not. This was a Boer War level failure.)
Second, does the electorate even consider Mr. Trump to be an honest-to-goodness Republican? The heavily tarnished image of the party might not rub off on him. Sure, Mr. Trump has monumental problems of his own. But his approval ratings have been trending upward as he becomes more closely associated with the party (hell, he’s about to become the head of the GOP, something that seems impossible even as I type these words), while the party’s numbers have been fairly flat. There might be a lesson here for those who breathlessly declaim that Mr. Trump will irredeemably ruin the GOP’s credibility. There’s already some reason to believe that voters are compartmentalizing their views Mr. Trump and the Republican Party, which is human, all too human.
 Data taken from http://www.pewresearch.org/data-trend/political-attitudes/republican-party-favorability/ and http://www.pewresearch.org/data-trend/political-attitudes/democratic-party-favorability/ – Note that I took the favorability ratings from the time closest too (but not after) the given election; for the 1996 election I had to use 1995 data. Also who knows what to say about 1992 with the third-party craziness and all? Not me.
 http://www.gallup.com/poll/124922/Presidential-Job-Approval-Center.aspx – An even better way to do this would be to add the candidate’s party’s approval rating to the candidate’s own approval rating and then compare it to the sum of his/her own approval rating and his/her party’s approval rating. But I lack that information and am too lazy to try to get it.