Why it matters: It’s the first congressional subpoena — that we know about — of one of President Trump’s children. The subpoena sets up a fight that’s unprecedented in the Trump era: A Republican committee chair pit against the Republican president’s eldest son.

It’s also a sign that the Russia investigations in Congress aren’t over despite the conclusion of special counsel Robert Mueller’s probe and despite Senate Majority Leader Mitch McConnell saying it’s time to move on from the Russia probe…

What we know: Cohen claimed in his testimony before the House Oversight Committee in February that Trump Jr. was more aware of the project than that. During the 2016 presidential campaign, Cohen testified, he briefed Trump Jr. and Ivanka Trump about the proposed Trump Tower Moscow project about 10 times.