It seems like Democrats really love having Mitch McConnell as Senate Majority Leader. Although the Senate battleground is certain to be better for Democrats in 2020 than it was in 2018 — a year when the Democratic vote reached an all-time high in a midterm election, coming within almost a million votes of the 2016 presidential election turnout — several top Democratic recruits announced this week that they won’t run for competitive Senate seats.

Republicans currently hold a 53-47 edge in the Senate. There will be at least 34 seats up for election in 2020, and 22 of those are currently held by Republicans. This is a much different picture than in 2018, when Republicans knocked off Democratic incumbents in North Dakota, Missouri, Indiana and Florida despite the fabled “blue wave” in the House races.

Only 12 Democrats will have to defend their seats in 2020, and most of those are pretty safe bets. Democrats need only pick up three seats this time around to win back control of the Senate — that is, if they also win the White House. But only two of the Republican incumbents up for re-election, Cory Gardner of Colorado and Susan Collins of Maine, represent states that lean Democratic. As CNN’s Harry Enten explained, 16 of the other 20 Republican-held seats “are in states that were 10 points or more Republican than the nation as a whole in a weighted average of the last two presidential elections.”

Despite the uphill challenge, if Democrats win by 8 million to 9 million votes nationwide — the same margin by which they regained control of the House, in a midterm election that saw the turnout rate among voters under 30 increase by 79 percent, relative to the last midterm in 2014 — they can plausibly pick up four seats, losing one (they must defend two seats of their own in Republican territory), and end up with a 50-50 split in the Senate. Assuming, of course, they have a Democratic vice president to break the tie.

That’ why the recent decisions by several top Democrats look worrisome. Many prominent and rising stars seem uninterested in winning the Senate and helping down-ballot Democrats. While too many Democrats are running for president, not enough are running for Senate.

Beto O’Rourke in Texas, Steve Bullock in Montana, and John Hickenlooper in Colorado all gave up opportunities to challenge potentially vulnerable Republicans for Senate seats, in order to run for the presidency instead. Coupled with the news that Democratic Sen. Joe Manchin is considering resigning his seat to run for governor in West Virginia, Democrats could find themselves losing ground in the Senate even if they manage to beat President Trump.

O’Rourke, who narrowly lost to Sen. Ted Cruz in November, concluded shortly thereafter that he’d forgo another U.S. Senate campaign — this time against Republican John Cornyn — to run for president instead. Cornyn has been in the Senate for 17 years, and was last re-elected with 62% of the vote. But he may be vulnerable precisely because he belongs to the pre-Trump Republican old guard. Cornyn’s approval rating in Texas is worse than that of Ted Cruz, whose polarizing demeanor won him the affection of ornery Lone Star Republicans. In a March 2019 UT/TT Poll, only 62% of Republican voters approved of Cornyn while 83% like Cruz.

Popular or not, Cornyn does have $7.4 million on hand. That may have been enough to scare away another top Democratic recruit.

A month ago, it felt inevitable that Rep. Joaquin Castro, chair of the Congressional Hispanic Caucus and twin brother of presidential candidate Julián Castro, would run against Cornyn. But after an extended period of mixed signals that made clear he couldn’t make up his mind, Castro announced this week that he would stay in the House.

Interestingly, the Austin American-Statesman reported that Senate Minority Leader Charles Schumer was not keen on Castro jumping to the Senate. Along with Sen. Catherine Cortez Masto of Nevada, the chair of the Democratic Senatorial Campaign Committee, Schumer focused on recruiting MJ Hegar, an Air Force veteran who narrowly lost a House race last year in a Republican-leaning district north of Austin. Hegar, who lost to Rep. John Carter by less than three points, announced last week that she will challenge Cornyn. She has never run a statewide campaign.

A significantly more famous Democratic woman, who also narrowly lost a race against a Republican man in the South last year, announced this week that she won’t seek a Senate seat either. After her sudden rise to national celebrity in the 2018 Georgia gubernatorial race, Stacey Abrams was widely expected to mount a run for Senate in 2020 against Sen. David Perdue, a standard-issue conservative Republican with no particular cult following. On Tuesday, however, Abrams announced that she would not run.

It’s true that no Democrat has won a statewide election in Georgia since Zell Miller, the former governor, won a Senate seat in 2000. But Schumer views Perdue as a top Democratic target, and recruited Abrams heavily. He chose her, for instance, to give the Democratic response to Trump’s State of the Union this year. She would likely have had a formidable campaign infrastructure and enormous name recognition. In announcing her decision this week, Abrams said she wanted an executive role. The Senate, she said, is “not the role that best suits those needs.”

There may be logic to this. Abrams is only 45. Had she run for Senate this time around and lost — the race against Perdue would likely have been a toss-up — a third statewide campaign in 2022 would be much harder as a “perpetual loser.” Abrams is still reportedly considering a 2020 presidential bid, although she hasn’t taken any recent trips to Iowa, New Hampshire or even neighboring South Carolina. A 2022 rematch with Gov. Brian Kemp, who won by a sliver in an election many observers saw as tainted, is her most likely next political move. At the moment, she says she’s focusing on her voting rights project.

Her decision creates a wide-open field for the party’s nomination. Former Columbus mayor Teresa Tomlinson, failed House candidate Jon Ossoff and former acting Attorney General Sally Yates are all reportedly considering Georgia campaigns, but none have anything close to the same statewide name recognition as Abrams. Still, Schumer may be right to see this seat as vulnerable: Trump’s approval rating in Georgia is much lower than in other Southern states.

In Colorado, another top Democratic target, Trump’s approval rating is also underwater, standing at 39% in the latest Gallup poll. But former governor John Hickenlooper, by far the Democrat best positioned to oust the obviously vulnerable Sen. Cory Gardner, claims (like Abrams) that he’s not cut out to be in the Senate. What’s especially strange about this one is that Hickenlooper would likely have won that race. Instead, he’s running for president with what he must know is virtually no chance.

“As a senator, most senators don’t — you don’t become even the vice chair of a reasonably important committee until your third term,” Hickenlooper, who is 67, told Colorado Public Radio. “But by the time I got to my third term, I’d be 80.”

There’s yet another popular Democratic governor in a red-leaning state who also seems to have spurned Chuck Schumer for the impossible dream of a White House bid. MTN News reported this week that Montana Gov. Steve Bullock will announce his long-discussed presidential candidacy “in two weeks.” Bullock is, or was, the Democrats’ best hope to take on Republican Sen. Steve Daines.

Control of the Senate in 2021 will likely come down to Donald Trump and whether he can carry Republicans in blue and purple states across the finish line. Despite the crippling loss of star power this week, Democrats will still likely have a president with approval ratings hovering around 42% come Election Day next year.

So a Democratic Senate majority isn’t impossible. It would take work and focus, and it might be an uphill battle even if Democrats win the presidency in 2020. According to New York Times statistician Dave Wasserman, you can win a Senate majority while representing only 18% of the U.S. population. The Senate is a highly undemocratic institution, which is a much bigger story. But it is what it is, for the moment, and Democrats can’t figure out whether to go after the prize or give up.