We know that Donald Trump and his top aides have held a range of meetings with Russian officials—some ordinary (Secretary of State Rex Tillerson’s tense visit to Moscow after U.S. airstrikes in Syria), some extraordinary (Trump revealing sensitive counterterrorism intelligence to the Russians in the Oval Office), and some thoroughly perplexing (a sit-down in which Trump did—or did not—accept Vladimir Putin’s denial of Russian interference in the 2016 U.S. election). We know this because the U.S. and Russian governments publicized these meetings, if not the precise details of their proceedings.
But there’s a whole other class of meetings between the Trump camp and the Kremlin: those that haven’t been disclosed to the public until the media discovered them. Trump’s second conversation with Putin at the G20 summit in Germany, reported on Tuesday, belongs in this ever-expanding category. And that—not the fact that the American president got to talking with his Russian counterpart at dinner, not even the fact that the talk only involved Trump, Putin, and a Russian interpreter—is the primary reason (as far as we currently know) that the encounter is significant. It’s the key and puzzling theme that runs through a range of Trump camp-Russia meetings, from the probably banal to the potentially sinister, from the campaign into Trump’s presidency. Here’s a guide to the different kinds of encounters that, for whatever reason, Trump and his allies didn’t mention at the time.