The Most Nationalized House Election Since Eisenhower?

It has become fashionable of late, particularly among liberal pundits, to argue that the future of the Republican Party depends on its leaders severing all connections with Trump and his movement.  For a number of reasons that I will discuss in future posts, I think this is profoundly stupid advice for Republicans to follow.  But whatever one’s views on the topic, one thing is clear: if you are House Speaker Paul Ryan, you want Donald Trump to do well tonight – bigly, even.

The reason is that in recent years, House elections have become increasingly nationalized.  That is, the outcome in any particular House election increasingly is affected by factors outside that district, including how well the House candidate’s party does in the presidential election. There are a number of reasons why this is the case.  A big factor is party sorting, which has made the Democratic Party and the Republican Party increasingly homogeneous in terms of ideology.  That means the party brand name serves as a more important cue for voters during House elections.  A second reason is developments in how campaigns are funded, with an increasing percentage of candidate funds coming from outside the House district as congressional candidates are more likely to look outside their own districts for funding by tapping into more ideologically-oriented issue activist.. There are other reasons that I’ve discussed elsewhere.

Several decades ago, of course, the legendary House Speaker Thomas “Tip” O’Neill proclaimed that all politics is local.  But that has long ceased to be the case, at least when it comes to the House.  Just how nationalized are House elections?  One crude way to estimate the relative proportion of the House vote that can be explained by national and local forces is to regress the House vote in any district against the presidential vote in that particular district as well as the prior House vote. The coefficient for the presidential vote can be viewed as a proxy for national forces, while the House coefficient represents the local component.  I’ve presented previous versions of this data before, but Middlebury College students Tina Berger and Martin Naunov have updated it through the 2014 midterms.  Here’s a chart that shows the relative influence of local and national forces dating back to 1954 for midterm elections.  (Note that I have skipped elections immediately following decennial redistricting, since it is impossible to calculate the prior presidential or House vote for that district.)  These tables only include contested House races.

And here are the results for presidential election years.

As you can see, there has been a steady increase in the relative impact of the presidential vote on the House vote for both presidential and midterm House elections, reflecting the increasing nationalization of House races more generally. In fact, 2014 saw the most nationalized House elections dating back to Eisenhower’s presidency. I have no reason to believe that this trend will reverse itself in today’s House races.  For better or for worse, then, the fate of the Republican House majority rests in large part on Donald Trump’s somewhat tiny hands.  Fortunately for Republicans, the much-discussed (by pundits) electoral landslide for Clinton does not seem imminent, at least if Drew Linzer’s forecast model is correct (and it has been consistently the best forecast model out there.)  While Linzer is predicting a relatively comfortable victory for Clinton of about 52% in the two-party popular vote, that’s probably not going to be enough to tip the House to the Democrats. Of course, the better the Donald does tonight, the better for the Republican House majority – at least if recent trends hold.  If I’m Paul Ryan, then, I’m secretly hoping that the Donald does very very well tonight.

I’ll be on a bit later tonight on this site to blog tonight’s election results live from the [Karl Rove] Crossroads Café at Middlebury College.  Hope you can join in!