Barack Obama found in 2009 that winning a presidential election is one thing but getting the United States Senate to do what you want is a rather different thing. Next year, Donald Trump will have Republican congressional majorities at his back, but that doesn’t necessarily mean the Senate will back all of his priorities.

And already, as the transition enters its second week, foreign policy is emerging as a potential trouble spot for Trump. It started with Dave Weigel’s report Tuesday that Sen. Rand Paul would be inclined to oppose John Bolton or Rudy Giuliani as secretary of state, arguing gingerly that he is merely defending the very positions Trump ran on:

“It’s important that someone who was an unrepentant advocate for the Iraq War, who didn’t learn the lessons of the Iraq War, shouldn’t be the secretary of state for a president who says Iraq was a big lesson,” Paul said in an interview this morning. “Trump said that a thousand times. It would be a huge mistake for him to give over his foreign policy to someone who [supported the war]. I mean, you could not find more unrepentant advocates of regime change.” Paul argued that both Giuliani and Bolton, the people whose names have circulated most widely, “have made it clear that they favor bombing Iran.” Choosing either for a key administration job, he said, would go back on the “America First” foreign policy that helped Trump win the Republican primaries, to the surprise of the Republican Party foreign policy establishment.

But later in the day, John McCain came out with a statement from the opposite direction, cautioning Trump against trying to make good on his campaign pledges to improve relations with Vladimir Putin and Bashar al-Assad, denouncing their “barbaric war against the Syrian people.”

John McCain steps out, warns Donald Trump when it comes to his administration’s potential relationship with Russia pic.twitter.com/4LiVKZA8rU — James Arkin (@JamesArkin) November 15, 2016

Relatively few senators care very much about foreign policy. But those who do care tend to care a lot, and neither Paul nor the hawkish wing of the GOP has a ton of personal confidence in Donald Trump.

The easiest way for Trump to square this circle would be to simply pick a few Republicans who are generally well-regarded. The same kind of people you’d expect to have served a John Kasich administration, in other words, rather than controversial and polarizing choices. Senate Democrats from red states would be glad to not have a big confirmation fight on their hands, and if they vote to confirm a Trump appointee, it wouldn’t matter what Rand Paul thinks.

But to do that, Trump would have to look outside the circle of figures who were personally loyal to him during the primary and choose instead from the much broader universe of right-of-center figures who were leery of him but are now hoping for the best.

Watch: How Donald Trump thinks about foreign policy