Cars pass by a billboard showing President-elect Donald Trump and Russian President Vladimir Putin placed by members of the pro-Serbian movement in the town of Danilovgrad on Nov. 16. (Savo Prelevic/Agence France-Presse via Getty Images)

Over the Thanksgiving break, I wrote something about how foreign actors will try to navigate American foreign policy when President-elect Donald Trump is tweeting blatant falsities at all hours of the day. But there was a hidden assumption I made in that piece that is worth questioning going forward: will Trump actually be the decider on American foreign policy?

There are some valid reasons to ask that question. There’s the issue of interest — maybe Trump doesn’t care that much about foreign affairs not involving beauty pageants. By his own choosing, Trump hasn’t received many intelligence briefings since becoming the president-elect, whereas Vice president-elect Mike Pence has been briefed on an almost daily basis. Trump also made it clear during his first week as president-elect that his policy priorities would be enriching his family’s bottom line domestic in nature.

There’s the issue of knowledge. Trump might have a coherent foreign policy worldview, but he doesn’t actually know that much about world politics. His sitdown with the New York Times last week simply reinforced that image.

There’s also the issue of management. On the one had, there are plenty of reports about how Trump is a micromanager. There are also indications, however, that Trump wants a decentralized White House structure. There is also the reality-show nature of Trump’s waffling over who will be his secretary of state. This will make it particularly difficult for outside observers to parse out Trump’s intent — because unlike past presidents, he seems to delight in the feuding and fussing.

When Trump gets around to announcing his secretary of state, a lot of people will proclaim it to be the most important signal yet on the direction of Trump’s foreign policy. Don’t buy that argument. George W. Bush appointed Colin Powell as his first secretary of state, and I think it’s safe to conclude that Powell did not really drive American foreign policy. Barack Obama picked Hillary Clinton, but the dirty little secret of the past eight years is that most of American foreign policy was run out of the White House and not Foggy Bottom.

So how will outside observers be able to tell if Trump is actually running American foreign policy? Let me suggest that the ideal bellwether will be the U.S. relationship with Russia.

Russia is one of the few areas where Trump was perfectly consistent throughout the campaign. Trump praised Russian President Vladimir Putin from the outset and refused to join in standard U.S. criticisms of him. He rejected intelligence briefings that concluded Russia had played a pivotal role in hacking the Democratic National Committee. After Pence sounded a more hawkish tone on Russia’s role in Syria during his vice presidential debate, Trump pushed back again, saying, “He and I haven’t spoken, and he and I disagree.” McClatchy reports that since he was elected, Trump has talked more with Putin than any other world leader. And here’s what he told the New York Times last week:

I would love to be able to get along with Russia and I think they’d like to be able to get along with us. It’s in our mutual interest. And I don’t go in with any preconceived notion, but I will tell you, I would say — when they used to say, during the campaign, Donald Trump loves Putin, Putin loves Donald Trump, I said, huh, wouldn’t it be nice, I’d say this in front of thousands of people, wouldn’t it be nice to actually report what they said, wouldn’t it be nice if we actually got along with Russia, wouldn’t it be nice if we went after ISIS together, which is, by the way, aside from being dangerous, it’s very expensive, and ISIS shouldn’t have been even allowed to form, and the people will stand up and give me a massive hand. You know they thought it was bad that I was getting along with Putin or that I believe strongly if we can get along with Russia that’s a positive thing. It is a great thing that we can get along with not only Russia but that we get along with other countries.

So, in contrast with a lot of other national security issues — like, say, torture — Trump isn’t simply echoing what the last person who talked to him thinks about it. This is a rare case of a specific foreign policy where he has fixed and frozen preferences.

Trump’s bromance with Putin has some of my colleagues who focus on Russia in a positively giddy mood. If you want to see warmer U.S. relations with Russia, then it would be hard to ask for a more solicitous president than Mr. Trump. And here we get to the question of whether it will matter.

There’s the small issue of the other policy principals on Trump’s foreign policy team. We already know that Pence is more hawkish on Russia. And here’s Trump’s possible pick for Director of National Intelligence on Russia’s role in the 2016 campaign:

Then there’s Congress. Several key GOP players in Congress have made it pretty clear that they disagree with Trump’s approach to Russia. This includes people on Trump’s transition team in intelligence. It’s worth remembering that when presidents have tried to build warmer relations with the USSR or Russia, Congress has often managed to throw some sanctions sand in the gears (see: Jackson-Vanik, Magnitsky Act).

So pay attention to what happens to U.S. relations with Russia once Trump becomes president. If there really is another attempted reset, then it’s a data point in favor of Trump being the foreign policy decider. If he doesn’t get his way on this issue, however, then he’s going to have a devil of a time redirecting American foreign policy on issues he cares less about.