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2018's open House seats

New today: Republican Rep. Tom Rooney won't run for re-election in a district Trump won by 27 points in 2016.

By the time Nov. 6 rolls around, there will be at least 53 vacated House seats up for grabs — more than two-thirds of those are held by Republicans this term. The openings are significant because incumbents have outperformed non-incumbents of the same party in similar districts by about seven points in the last decade or so, per the New York Times.

Note: The Cook Partisan Voter Index is a measure of how liberal or conservative a district leans based on the two most recent elections; Data: Daily Kos Elections and Cook Political Reports; Chart: Chris Canipe / Axios