The votes haven’t all been counted in the 2018 Senate elections, but we know the size of the incoming majority will be critical, because the 2020 Senate map offers limited initial takeover opportunities for both parties.
Of course, it’s too early to tell what the presidential race will look like, how voters will feel about the economy and direction of the country, and whether they’ll believe more Democrats are needed in Washington.
The next class of senators was last elected in 2014 — a great midterm year for Republicans in which they gained nine seats. But the consequence of having a good year in the Senate is having to defend those seats six years later. Republicans will be playing more defense next cycle, defending at least 21 Senate seats while Democrats will be defending 12 — the opposite dynamic from this cycle.
The shape of the presidential race matters, considering 2016 was the first time in the history of popularly elected senators that the Senate outcomes matched the presidential outcomes in every state.
If you apply the 2016 presidential results to the 2020 Senate class, the result is no net change. Using the 2012 presidential results as a guide, Democrats would gain two Senate seats by losing Alabama and picking up Colorado, Maine, and Iowa. If the 2008 presidential results applied, Democrats would gain three seats by losing Alabama and taking over Colorado, Iowa, Maine, and North Carolina.
Watch: Now That That’s Over (Mostly), Roll Call Looks Ahead to 2020
Usually the races are more complex and the size of the Senate playing field will also depend on retirements, recruitment and primaries, beyond the presidential map.
What immediately stands out about the 2020 Senate landscape is the initial lack of vulnerable Democratic senators.
Doug Jones of Alabama is the only Democratic senator representing a state that Donald Trump and Mitt Romney carried in the last two presidential elections. Jones was elected in a December 2017 special election with 50 percent over Roy Moore, who had significant baggage from his past. Jones will start as an underdog in his re-election race.
Gary Peters of Michigan is the only other Democratic senator from a state that Trump won in 2016 (albeit with 47.5 percent). But Obama carried Michigan with 54 percent and we saw in 2018 that most of the Democratic senators from states Trump carried narrowly were at limited risk. (And a Democrat won the governorship in Michigan on Tuesday night.)
At least two Democratic senators who are up for re-election are eyeing presidential bids: Cory Booker of New Jersey and Jeff Merkley of Oregon. If they chose to give up their seats to focus on the White House, competitive primaries would likely ensue, but Democrats would start as favorites to hold both states.
Most of the action on the Democratic side could be in primaries to take on GOP senators. Senate Democrats largely avoided them this cycle because they had savvy incumbents seeking re-election in challenging states. But open opportunities to take on Republicans will be a different story. The crowded and competitive House primaries in 2018 are likely a precursor to what will happen in the Senate next cycle. And those races will likely play host to fights over ideology and the power of the establishment, with potential general election consequences.
Democrats could also see a challenge to one of their incumbents. According to a September story in The New York Times, Rep. Seth Moulton is considering a primary challenge to Ed Markey of Massachusetts. The race wouldn’t have general election consequences but would be another sign of anti-establishment fervor within the Democratic Party.
Every cycle, there is a least one retirement and Sen. Dick Durbin of Illinois might be one of them. Democratic Rep. Cheri Bustos is close to the senator and would be an obvious successor if a spot in House leadership or a spot as a running mate on a presidential ticket doesn’t conflict.
Based on the 2016 presidential results, Sens. Cory Gardner of Colorado and Susan Collins of Maine would be the most vulnerable senators, as the only two Republicans in states that Clinton carried in 2016.
There won’t be any shortage of Democrats looking to take on Gardner, particularly after his vote to confirm Justice Brett Kavanaugh and his cycle as chairman of the National Republican Senatorial Committee. And Democratic donors around the country rallied to raise more than $4 million for a Collins challenger in the wake of the Kavanaugh hearings.
Sens. Joni Ernst of Iowa and Thom Tillis of North Carolina represent Trump states that Obama carried previously and should be regarded as initially vulnerable as well. Trump and Romney carried Arizona, but uncertainty surrounding the late John McCain’s seat could make it interesting. The seat will be on the ballot in November 2020.
Republican retirements are also a possibility. Sen. Pat Roberts of Kansas is 82 years old and faced a competitive primary in 2014, which he won 48 percent to 41 percent. Sen. Jim Inhofe of Oklahoma is 83 years old, but doesn’t appear to be going anywhere. Competitive primaries are likely if either or both seats open up.
Some GOP incumbents could face primary challengers. For Tennessee Sen. Lamar Alexander, that could be Mark Green, who hasn’t even been sworn in yet as the congressman from the 7th District. Alexander won his 2014 primary by 9 points and with just less than 50 percent against six candidates.
Nebraska Sen. Ben Sasse has been a vocal Trump critic, which should draw him a primary challenger, even though there isn’t an initial obvious choice. With Nebraska likely to lose a congressional seat before the 2022 elections, Rep. Jeff Fortenberry might attempt a jump to the Senate in 2020 instead of facing off against fellow Reps. Don Bacon or Adrian Smith in a primary down the road.
Sen. Lindsey Graham of South Carolina looked likely to draw a primary challenge after being critical of Trump during the 2016 campaign. But he’s since done a 180 and was given credit for turning around Kavanaugh’s confirmation.
One of the most fascinating races in the country next cycle could be in Kentucky. Sen. Mitch McConnell has proved his skills as majority leader and as a campaigner, but his unfavorable rating has climbed over the years and he seems likely to face another competitive race.
While the presidential race will suck up most of the oxygen in the 2020 room, the fight for the Senate should once again be a prime battle.
Correction, Thursday, 4:35 p.m. | An earlier version of the 2020 Senate map should have identified Arizona as a state that will host a Senate election that year.