With election Day 2016 a small over 2 months away, plenty of political experts are projecting democrats to gain seats in both the House and Senate. Yet winning the 30 seats they should wrest manage of the home from the republicans is normally seen as a longer shot than the 4 or 5 Senate seats they’d need to lead the chamber (depending on even if it is or no Hillary Clinton is chosen president and also Tim Kaine, as vice president and president of the Senate, has a tie-breaking vote).

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Shifts of that magnitude room uncommon yet not unprecedented: In three of the past 12 two-year election cycles, one party has racked up a net get of 30 seats or more (most recently in 2010, when the Republicans had a net obtain of 63 seats). For this reason we assumed it to be worthwhile to take it a closer look at the situations under which house seats do, and also don’t, move from Republican to democratic or vice versa. (In redistricting years, us excluded residence districts that were either freshly created and those therefore radically redrawn the no incumbent ran in them.)

One of the best obstacles to large swings native one party come the other is that so few incumbents shed their re-election bids. ~ above average due to the fact that 1992, 93% of residence members who actually look for re-election have won. Also in 2010, the re-election rate fell to “only” 85%, with 338 the the 396 representatives running for re-election retaining their seats.

Those statistics are necessary for an “out” party in shaping the strategy to obtain seats because knocking turn off incumbents has produced much more seat switches than has actually picking up open seats. In 2014, because that instance, 13 that the 19 chair switches were due to incumbent defeats. In 2010, a near-record year because that seat switches, 55 incumbents to be unseated (one in a primary, the rest in the general).

It’s also less usual for incumbents to lose their party nominating primaries, however when they execute their party practically always maintain the chair anyway. Since 2000, a full of 39 home incumbents have lost their primaries; in only five of those cases did your seats upper and lower reversal to the various other party.

Given the ease with which many incumbents success re-election, party strategists and media pundits often look for pickup opportunities in open up seats – occasioned through the incumbent’s retirement, resignation, fatality or decision to run for one more office. But open-seat switches have become much scarcer the past few election cycles. Out of 44 open seats in 2012 (not counting those developed by redistricting), just seven (16%) switched parties; in 2014, only six the 43 open up seats, or 14%, switched from one party to the other. As freshly as 2010, much more than a third of the open seats that year (14 out of 39) switched parties.

The decline the split-ticket voting is another challenge to those seeking to flip manage of the House. In presidential-election years, the overwhelming majority of home districts poll the same way for Congress together they do for president: In 2012, for instance, just 26 the the 435 house districts split their vote. And also when districts carry out split, it’s usually to retain their incumbent representative (or his or her party), no boot them out of office. In all but two of the 27 districts that switched parties in 2012, the presidential and House votes to be aligned; in 2008, 18 the the 31 switched-seat districts were an in similar way aligned. (The two years through the many seat switches in recent decades, 1994 and 2010, were both midterm elections.)

So, what’s the state of play in this year’s residence races? while a few states have yet to hold their primaries, together of this writing 388 incumbents are running because that re-election, 219 Republicans and also 169 Democrats. (Five other incumbents, 3 Republicans and also two Democrats, also had seek re-election however lost your primaries.) 16 Democrats and 25 republic retired or space seeking another office; one Democrat passed away this summer, leaving his seat open, and because of court rulings there room three newly redrawn districts with no incumbent.

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The consensus amongst political experts is that only around three dozen house seats are realistically “in play” this year. The Cook political Report, because that instance, rates 19 seat (16 at this time held by Republicans, 3 by Democrats) together “toss-ups”; seven seats (four of which space now held by Republicans) space competitive however lean Democratic, when 11 GOP-held seats are rated as leaning Republican.