On the surface, this would seem like a head-scratcher: A Democratic senator is meeting with President-elect Donald Trump on Friday, and in her statement announcing the meeting, Sen. Heidi Heitkamp (N.D.) sounded pretty open to crossing party lines to serve in his administration.

The operative sentence here (my emphasis added): “Whatever job I do, I hope to work with the president-elect and all of my colleagues in Congress.” Also, she made sure to make it clear Trump was the one inviting her.

When we zoom out and look at who Heitkamp is — or, more accurately, the electoral challenge she faces in the very near future — the fact that she seems eager to jump ship starts to make more sense. And if it happened, it'd be very good news for Republicans, both in the Senate and for President Trump.

Heitkamp's reelection to a second term in 2018 is an uphill battle with no guarantees. The 2018 midterms are shaping up to be the story of endangered, red-state Democrats trying desperately to hold their seats, and Heitkamp is arguably the most endangered of this group. She scraped out a win in 2012, and Trump won the state with 63 percent of the vote — one of his largest margins of victory anywhere.

Democrats may not be able to come to Heitkamp's rescue as much as she'd need them to. They will be spread thin trying to defend at least four other Heitkamp colleagues in states where Trump won by 19 points or more (Joe Manchin III in West Virginia, Joe Donnelly in Indiana, Claire McCaskill in Missouri and Jon Tester in Montana).

Heitkamp could battle it out for two years only to have a so-so shot at reelection. Or she could move to a high-profile job where she wouldn't have to run for election ever again (that is, unless she wanted to). If she harbors any political ambitions beyond the Senate, Option Two seems like the best way to help her get there — even if it means Senate Democrats are less likely to be able to take back control of the Senate because of it.

(Update: Here's incoming Senate Minority Leader Chuck Schumer (D-N.Y.) declining to talk about the possibility of Heitkamp bailing, which, in Washington Speak, suggests he's not happy about it.)

(Another update: After Politico reported Trump is also considering Manchin for the energy secretary job, his office said he had no knowledge of it, but Manchin didn't rule out working in a Trump administration. Such a scenario would double Senate Democrats' problems I describe below by giving Senate Republicans a chance to take not one but two red-state Democratic-held seats.)

We should caution that we don't know if Heitkamp is joining the Trump administration. There's no word on whether Trump is even considering Heitkamp for a Cabinet post. They could just be meeting to chat about the high-profile protests against the Dakota Access pipeline.

But if Trump does manage to install Heitkamp in his administration, it could mean Republicans hold onto their majority in the Senate for the next two, maybe even four years. If Heitkamp leaves office before her term is up, there will be a special election. And it's very likely, given the politics of the state, a Republican would win that contest.

Thanks to the magic powers of incumbency, that setup would almost guarantee that a Republican wins election to a full term in 2018. And that makes Republicans' effort to keep and even grow their majority that much easier.

For Trump, even the impression that a Democrat wants to work for him is a huge PR victory.

Heitkamp's meeting with Trump on Friday is unusual. She is just one of a handful of congressional Democrats who have met with Trump and pretty much the only Democrat we know of who seems open to a job in his administration. (Rep. Tulsi Gabbard (Hawaii) stopped by the other week to talk noninterventionist policy in Syria.)

By welcoming a high-profile congressional Democrat into his administration, Trump can try to claim some much-needed bipartisan legitimacy. At the very least, the fact that one Democrat seems willing to join his administration helps soften his image a bit. It's a bonus that Heitkamp is a woman, given that Trump's past three Cabinet-level choices have all been white men.

If Heitkamp wants to join Trump's administration, it would be terrible news for her party — but great news for Republicans, and, potentially, her.