When President Trump held his second, previously undisclosed meeting with Russian President Vladimir Putin during the G20 summit last week, he broke with longstanding policy by using Putin’s translator rather than having one of his own.

That’s a potentially serious problem because Putin now has the only record of the meeting — and is free to use it, or distort it, for political gain.

Trump’s decision to effectively wing it during his hour-long meeting with Putin at a social dinner wasn’t simply a casual choice by a president who isn’t well-versed in the finer points of diplomacy. Instead, it means the US has no record of what was discussed, what was disclosed, or what was promised. Russia does. That gives Putin a major advantage in his future dealings with Trump and in his ongoing PR war with the US.

In effect, Russia could say something happened during the meeting that may or may not have occurred. It’s hard to rebut since the only American who knows what happened is Trump.

Presidents usually have aides present for these kinds of meetings; past US leaders were unlikely to put themselves in this position with anybody. “We wouldn’t even do that for an hour with the head of the United Kingdom,” Julie Smith, a Russia expert and former White House official, told me about Trump’s decision to meet so informally with Putin. “Any normal leader wouldn’t do this.”

That’s also a concern for Strobe Talbott, a former deputy secretary of state and president of the Brookings Institution. When the news of the meeting broke Tuesday night, he tweeted, “POTUS compromised. Kremlin has the only record of the exchange, free to doctor it or use it to nefarious purpose.”

Putin and Trump, we now know, have met twice. And it’s clear that both times, Putin came out ahead.

Putin got the better of Trump at the G20

Putin got a lot more out of the first, pre-planned meeting on July 7 than President Trump did.

Trump appeared to accept Putin’s denials of any Russian election interference at face value, even though the entire US intelligence community assessed that the Kremlin mounted a sophisticated campaign to help him win the White House.

That wasn’t all. Russian Foreign Minister Sergei Lavrov, who attended the first meeting, told press that Trump claimed some in the US were “exaggerating” how much Russia affected the election’s outcome during the discussion — effectively dragging Moscow into Trump’s partisan wars at home.

And because of Trump’s lack of caution during the second meeting, the Kremlin has much more information about what transpired than the White House does.

“Because Trump is so inexperienced, there’s a concern he’s getting played by Putin,” Ian Bremmer, who was the first to report the second meeting and is president of the political risk consultancy Eurasia Group, said in an interview.

Whether Trump is being played or not, the two G20 meetings make clear Putin is better at the art of the deal than the president is at this point.

“Who knows what price we’ll pay for it?” Smith said.