The political world will be a three-ring circus over the next two years, and while the contest for the presidency will obviously dominate, there will be plenty to watch in the House and Senate rings as well.

Democrats start out with 235 House seats to 199 for Republicans, with one vacant seat due to the disputed outcome in North Carolina’s 9th Congressional District (a special election is likely to follow). This means that the GOP will need a net gain of either 18 or 19 seats, depending upon the outcome in North Carolina.

Democrats will be defending 31 seats in districts that voted for Donald Trump in 2016, but equally important, there was about a 7-point boost for Democrats in the overall popular vote in House races from 2016 to 2018. Whether that persists is anyone’s guess. Republican pollster Glen Bolger points out that the House has now changed parties under four consecutive presidents: in 1994 under Bill Clinton, 2006 with George W. Bush, 2010 with Barack Obama, and now 2018 with Trump.

Though all these swings occurred in midterm elections rather than in presidential years, this Democratic majority is still precarious given the volatility of American politics today and the growing proclivity of straight-ticket voting. One thing worth watching is this geographic sorting that we are seeing, with Democrats dominating in urban and suburban districts and Republicans winning small-town and rural constituencies. The challenge for the GOP is that there are more of the former than the latter.

The Senate, currently split with 53 Republicans and 47 Democrats, would seem to be up for grabs given that Republicans have 22 seats up next year to just 12 for Democrats. Democrats would need a four-seat net gain if the GOP retains the presidency, three seats if Democrats prevail. But this ratio is a bit deceptive. The 22 GOP seats up doesn’t quite match the exposure Democrats had with 24 seats up in 2018, and the vast majority of the Republican seats up are in solidly-to-strongly GOP states; none are deep in enemy territory for the GOP. Sens. Cory Gardner of Colorado and Susan Collins of Maine are the only two GOP incumbents up in states that voted Democratic in the 2016 presidential race; Colorado voted for Hillary Clinton by 5 points, Maine by 3 points.

In the last few years, there has been an unprecedentedly high correlation between presidential and senatorial outcomes in states, so this is an important statistic to monitor. Five other Republicans are up in states that Trump won by single-digit margins: Sens. Martha McSally of Arizona and Thom Tillis in North Carolina, which are states that voted for Trump by 4-point margins; Sen. David Perdue in Georgia, a state that voted Republican by 5 points; and Sen. John Cornyn of Texas, which voted for Trump by 9 points.

Conversely, Democrats have two seats up in states that voted for Trump and four seats in states that voted for Clinton by single digits. The lone Democrat up in heavily Republican territory, Sen. Doug Jones in Alabama—where Trump won by 28 points—is reminiscent of the five Democratic incumbents who were up in 2018 in states that Trump carried by 19 points or more. Sens. Heidi Heitkamp of North Dakota, Joe Donnelly of Indiana, and Claire McCaskill of Missouri all lost reelection, while Sens. Joe Manchin of West Virginia and Jon Tester of Montana managed to survive. The other Democratic incumbent to lose last year was Sen. Bill Nelson in Florida, a state that Trump won by a point. Also up next year is Democratic Sen. Gary Peters in Michigan, where Trump won by his narrowest margins, three-tenths of a percent.

The four Democrats up in states that Clinton won by single digits are Sens. Jeanne Shaheen in New Hampshire (Clinton by four-tenths of a point), Tina Smith in Minnesota (2 points), Mark Warner in Virginia (5 points), and Tom Udall in New Mexico (8 points).

Looking at the dozen states that would seem worth keeping an eye on, six from each side, neither party looks disproportionately vulnerable. But one potential ‘X’ factor is that there are a dozen incumbents whose seats are up in 2020 who will be 70 or older by Election Day—five Democrats and seven Republicans. One of those, GOP Sen. Lamar Alexander of Tennessee, will be 80 by next year’s election and has already announced plans to retire.

This story was originally published on nationaljournal.com on January 4, 2019

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