Just what did Donald Trump and Vladimir Putin discuss in their private meeting Monday in Helsinki? Trump himself bragged about the impact of their tête-à-tête yesterday on Twitter, promising progress on a number of fronts — terrorism, nuclear proliferation, North Korea, Ukraine, and trade. Trump didn’t mention any specific agreements that might have been reached, but the Russians have already started bragging that they’ve picked up some big wins, which has a lot of people in Washington scratching their heads:

Two days after President Trump’s summit with Russian President Vladi­mir Putin, Russian officials offered a string of assertions about what the two leaders had achieved.

“Important verbal agreements” were reached at the Helsinki meeting, Russia’s ambassador to the United States, Anatoly Antonov, told reporters in Moscow Wednesday, including preservation of the New Start and INF agreements, major bilateral arms control treaties whose futures have been in question. Antonov also said that Putin had made “specific and interesting proposals to Washington” on how the two countries could cooperate on Syria.

But officials at the most senior levels across the U.S. military, scrambling since Monday to determine what Trump may have agreed to on national security issues in Helsinki, had little to no information Wednesday.

At the Pentagon, as press officers remained unable to answer media questions about how the summit might impact the military, the paucity of information exposed an awkward gap in internal administration communications. The uncertainty surrounding Moscow’s suggestion of some sort of new arrangement or proposal regarding Syria, in particular, was striking because Gen. Joseph Votel, who heads U.S. Central Command, is scheduled to brief reporters on Syria and other matters Thursday.

The possible existence of verbal agreements isn’t as much of an issue as one would first think. Anything agreed to verbally could just as easily be reversed or completely denied, for one thing. If it doesn’t exist on paper, then it’s not even technically an executive agreement, and would only have the weight that Trump gives it at any one time. It sounds more like Russia trying to make political hay while the sun shines on Helsinki, but even if it’s not, any bad ideas are likely to die a quick death when Mattis & Co take a look at them.

If they do exist, Lindsey Graham pointed out in this video clip, it doesn’t necessarily mean they’ll be bad. It does mean that the White House should brief Congress soon on them, however:

That’s why Senate Democrats wanted to subpoena Trump’s translator in Helsinki, just in case Trump himself was less than forthcoming. “If the president won’t share that information with us,” Jeanne Shaheen (D-NH) told ABC News, “then the interpreter is the only person we can look to.” Republicans are reluctant but haven’t ruled it out entirely:

Corker said Wednesday he understands why Democrats would make such a request and is seemingly open to it.

“All of us want to know what took place in that meeting,” Corker told reporters.

“That’s been something that’s been suggested, but again, is that really appropriate? We have to ask,” Corker said. “One of the lowest levels that we’ve seen in our foreign policy is what we saw a couple of days ago in Helsinki, and I think all of us are incredibly still sort of wondering what thinking is taking place.”

But he cautioned: “I don’t want us to lower ourselves … if it’s appropriate we’ll pursue it, if it’s something that truly should be executive privilege, we won’t.”

Jazz noted earlier that Congress likely has the authority to issue such a subpoena, but it’s unlikely to work. This falls squarely into executive privilege and exists in an arena where executive authority reaches its zenith — foreign policy. Congress has no role in negotiating with foreign powers, which would put them at an extreme disadvantage if the White House chose to fight such a subpoena in federal court. Unless there existed actual and objective evidence of a crime being committed — as opposed to a foolish foreign policy choice — Congress has no oversight role in these kinds of conversations between a president and another world leader.

That’s not to say, of course, that Trump shouldn’t share any private agreements with Congress, or at least its leadership. He should, and he should be prepared to defend them, especially since Trump will eventually need some buy-in to sustain any he might have made. Without that, Congress could well start impeding them, making them worthless.

In this case, perhaps a bigger worry would be whether Trump disclosed any significantly classified information in these discussions with Putin. If the conversation was as free-wheeling as Trump suggests and given his garrulous nature, it’s a distinct possibility that Putin learned a lot more than Trump did in this meeting. That’s why previous presidents didn’t enter into summits with Russian/Soviet leaders without a long amount of preparation and a specific topic and goal in mind. It’s also why many counseled against the Helsinki summit even before Robert Mueller rolled out twelve indictments last week, or at least a better structure for intermediate engagement.

As I wrote in my column at The Week, the big lesson here is that Trump needs to adhere to that model in the future:

So what should we make of Sheriff Trump? His diplomatic maneuvers over the last week — at NATO, in London, and now with Putin — indicate that Trump is a lot more comfortable confronting friends than malevolent and “unsavory” figures hostile to the U.S. Gorka was correct to write that America can ill afford not to engage with Russia, but this episode shows that Trump should leave that to deputies who are better prepared for those engagements, both for Trump’s own sake and for the country’s.

This should be Sheriff Trump’s last foreign summit without extensive preparation and an important agreement ready to sign after being fully vetted first by seasoned professionals.

The outcome demonstrates something else, too — a limit to Trump’s support on Capitol Hill and within his own party. This time, it was the Republican establishment who played sheriff and Trump that got his reins yanked back. That’s a valuable lesson, one which puts more responsibility on the GOP to exercise those reins more vigorously in the future. To the extent that the sheriff keeps control and prevents chaos, the imposition of discipline will only help Trump in the long run.

That would have saved Trump a lot of headaches this week. We’ll see if he learns that lesson the next time he meets with Putin, which apparently is coming soon.