Based on the elections that have been called, Democrats will have 225 seats in the next House. They are leading in five of the 13 remaining seats. Henry Olsen concludes, “Come 2020, the GOP will need to gain only a dozen or so seats to retake the House, a mark it can easily meet by focusing on working-class Democratic districts and some close, mixed seats that Republican candidates barely lost this week.”
Republicans have not, however, tended to pick up many House seats during presidential-election cycles, even when they win those presidential elections. In 1988 (George H. W. Bush’s election), they won two fewer seats than they had won in 1986; in 2000 (George W. Bush’s election), they won three fewer seats than the election before; and in 2016 (President Trump’s election), they won six fewer seats than they had in 2014. Republicans’ best presidential-election year since Reagan left office was in 1992 — they picked up nine seats between the 1991 and 1993 Congresses — which I’m guessing reflects both Bill Clinton’s winning election with a minority of the popular vote and the GOP’s gaining ground because of redistricting and reapportionment.
If Republicans gain a dozen seats between the start of this next Congress and the start of the one after that, it will be their best presidential-cycle performance since 1984 (when they won 15 more seats than they had won in 1982). That doesn’t mean it’s impossible, but it provides a sense of the scale of the challenge.
Oh, and the last time control of the House flipped back and forth in two successive elections? Republicans won a majority in 1952 (with Eisenhower’s first election) and then lost it in 1954.