What does this mean? It means that Republicans are "coming home." Even in a terrible year for the GOP, they are not going to perform much worse in the national vote than 43-44 percent. In 2006, for example, Republicans took 44 percent of the national House vote, even as many polls leading up to Election Day showed Republicans in the high-30’s. In 2008, an even more politically horrific year for the GOP, Republicans garnered 43 percent of the national House vote. In both cases, Republican voters, many reluctantly, "came home" to the GOP in the end. What’s happening now is that these voters are coming home sooner. Given our intense polarization, and a president and a news media that fans those partisan flames, this shouldn’t be all that surprising.
Overall, about one-third to 40 percent of self-described independent voters approve of the job Trump is doing as president. And, as we know, how you feel about the president is correlated very closely to how you vote in a mid-term election.
In the latest Marist/NPR/PBS poll (April 10-13), for example, Trump’s job approval rating among independents is 38 percent. On the generic ballot question in that same poll, the congressional Republican gets 32 percent of the independent vote. A late April Quinnipiac poll showed Trump with a 33 percent job approval among independents, and 36 percent of independents say they will vote for a Republican in the fall.
So, let’s move this forward. We can make a pretty good case that undecided independent voters are ultimately going break along Trump approval ratings. So, if Trump’s job approval rating among independents is at 40 percent going into the election, it’s fair to assume that 40 percent of the undecided independent vote will go to the Republican candidate. It could be a bit better or a bit worse. In the Marist poll, for example, 32 percent of independent voters are undecided on their vote for Congress. If those 32 percent ultimately broke along Trump approval ratings, it would mean that a Republican candidate could expect to get 44 percent of independents.
However, a 44 percent showing among independents is a bit better than where Republicans were in 2006 and 2008. According to the exit polls, Republicans took just 39 percent of the vote among independents in 2006. In 2008, Republicans took 43 percent of the independent vote (a 4 point improvement from their 2006 showing), but Democrats also made up a larger share of the electorate in 2008 than in 2006. In 2006, the share of the electorate that was Democrat was 38 percent to 36 percent Republican. In 2008, that gap grew to 7 points (40 percent Democrat to 33 percent Republican). In other words, the closer to even that Democrats and Republicans are as a percentage of the electorate, the better Democrats need to do among independent voters.