The Enduring Republican Grip on the House

By Nate Cohn (shared by Scott Lyons) 

Whatever doubts existed about the Republican grip on the House should now be gone.

By picking up at least a dozen House seats in the elections last Tuesday, the Republicans cemented a nearly unassailable majority that could last for a generation, or as long as today’s political divides between North and South, urban and rural, young and old, and white and nonwhite endure.

Democrats might well reclaim the Senate and hold the presidency in 2016. But any Democratic hopes of enacting progressive policies on issues like climate change and inequality will face the reality of a House dominated by conservative Republicans. The odds that the Republicans will hold the Senate and seize the presidency are better than the odds that Democrats will win the House, giving the Republicans a better chance than Democrats of enacting their agenda.

After all of the remaining races are resolved, the G.O.P. will finish with about 249 seats. The Democrats would need to flip 32 seats to reclaim the chamber, but just 10 Republicans hail from districts with a Democratic Cook partisan voting index, a statistic to measure how far a congressional district leans toward the Republican or Democratic Party, compared with the national average. Because so many Republicans represent conservative districts, the G.O.P. might even retain the House in a “wave” election, like the ones that swept Democrats to power in 2006 and brought Republicans back to power in 2010.

The Republican grip on the House is underpinned by the tendency for Democrats to waste votes in heavily urban or nonwhite districts; the low Democratic turnout in off-year elections; the recent Democratic advantage in presidential elections; the advantages ofincumbency; and partisan gerrymandering. Ending partisan gerrymandering would not be enough to end the Republican advantage in the House, and last Tuesday’s results for state legislatures and for governors’ races further strengthened the Republicans’ ability to control the redistricting process.

The median House seat is held by a Republican who represents a district that voted for Mitt Romney in 2012, even in a year in which President Obama won by four percentage points nationally. The Republicans hold only 28 seats in districts that were carried by Mr. Obama. Many of these seats would fall to the Democrats in an anti-Republican year. The 12 newly elected Republicans who won seats in districts carried by Mr. Obama in 2012 are particularly vulnerable; many of these freshman Republicans could lose re-election in 2016.

Yet Democrats will have a struggle to win all of the seats held by Republicans that voted for Mr. Obama in 2012. The benefits of incumbency will allow many of these Republicans to defy even the most inhospitable conditions. And some of these Republicans, like Dave Reichert of Washington or Frank LoBiondo of New Jersey, are survivors of the 2006 and 2008 waves.

To gauge the problem for Democrats, look at the Cook partisan voting index, which measures districts by presidential votes. (A district with a D+5 P.V.I., for instance, has offered the Democratic presidential candidate a share of the popular vote 5 percentage points higher than the national average over the last two presidential elections.) If a future Democratic wave were to flip Republican-held seats at the same rate as the Democratic wave in 2006 or the Republican one in 2010 (that is, win about 30 percent of the R+3 seats, and 25 percent of the R+4 seats), they would gain about 27 seats — short of the 32 necessary to retake the House.

Democrats could do even better in the D+1-or-better seats than this scenario projects, but they could also do worse among the seats with a P.V.I. of R+6 or more Republican, where the estimate assumes the Democrats would win four seats. Republicans didn’t win a single seat that was so Democratic in 2010, and the big gains that Democrats made among these seats in 2006 were driven by problems among Republicans who were accused of corruption.

Even if the Democrats could retake the House in an anti-Republican wave, it probably won’t come with a Democratic president to take advantage of it. The party with the presidency rarely makes big gains in Congress. As my colleague Lynn Vavreck put it, the economy elects presidents; presidents elect Congress.

In other words, a Republican president is probably a prerequisite to a Democratic House. And even a Republican president might not assure another wave like 2006 or 2010, which itself would not even assure a Democratic House.