As Hillary Clinton begins to open up a fairly consistent lead over Donald Trump, and an unusual number of Republicans (though most of them not people running for office this year!) distance themselves from the mogul, the big question for down-ballot races is whether we’ll see the comeback of ticket-splitting in November.
To be clear, the idea that Republicans can save their congressional majorities, even as Trump goes down to a dreadful defeat, really does depend on a degree of ticket-splitting that has become less and less common in the 21st century. As the Washington Post’s Philip Bump notes, in 1992, 11 of the 34 states holding Senate elections produced different partisan results for the upper chamber and the presidency. In 2012, despite two Democratic Senate pickups in red states where the GOP candidate basically imploded, only six states split their results.
Reasons for this trend are well-known. In a process often called “the great sorting-out,” liberal voters have increasingly associated themselves with the donkey party, while conservatives have clustered in the shadow of the elephant. This “ideological polarization” has itself reduced ticket-splitting, as there are fewer opportunities for voters to find like-minded candidates on the other side of the partisan divide. But it has also increased “partisan polarization,” whereby voters prone to support one party (as self-identified partisans, or as independent “leaners” who almost always vote like partisans) tend to view those in the other party as enemies, or even as threats to the republic.
Democrats focused on down-ballot races this year are hoping that this pattern holds in 2016 — assuming Clinton wins, of course. But Republicans think (and certainly hope) that Trump’s exotic nature — amplified by the sheer number of GOP opinion-leaders who are keeping their distance from him — will send a signal to swing voters that the genial, glad-handing Republican pol who represents them in Congress or the statehouse has nothing to do with the rude, raging beast at the top of the ticket. There’s even a belief, more speculative than empirical, that if Trump really falls apart, it could make it easier for voters to split tickets — partly because everybody’s doing it, and partly because some will want congressional Republicans to act as a counterweight and safeguard against Hillary Clinton running wild, with her radical ideas of gender equality and access to health care and child care and so on. The last time there was any clear evidence of widespread “strategic voting” of this type, however, was all the way back in 1972: Democrats picked up Senate seats despite the debacle that George McGovern suffered at the presidential level. And back then, of course, it was very easy for voters in the South and parts of the West to vote for conservative Democrats down-ballot, along with the conservative GOP presidential candidate. In Georgia, where I lived at the time, there was even a ballot line where you could vote straight-party Democratic, right after you cast your presidential vote against the communistic McGovern.
There’s really not much clear evidence of how this is going to work out either way. Even as Clinton moves ahead at the presidential level, no one is seeing signs so far of a “wave election” which might sweep not only the Senate, but possibly even the House, into the Democratic column. Some vulnerable Republican senators (e.g., Rob Portman of Ohio and Pat Toomey of Pennsylvania) seem to be running ahead of Trump in their states, but often voters make up their minds late on such contests. The best-case scenario for Democrats is probably for 2016 to be the mirror image of 1980, when a presidential-level landslide gave Republicans wins in just about every close Senate race. After the Republican victory in 2014, such an outcome would also almost certainly produce big House gains as well, if not necessarily a majority. But whatever happens, it’s clear that a lot of the talk from Republicans about Trump and Clinton is really aimed at keeping the GOP rank and file in line — for the benefit of Paul Ryan and Mitch McConnell.