Newly revealed text messages between U.S. diplomats and Ukraine show ambassadors dangling a White House visit in exchange for an investigation of Donald Trump’s political opponent.

The chairmen of the House Intelligence, Foreign Affairs, and Oversight Committees released a series of text messages they say “reflect serious concerns.” The messages came from Kurt Volker, the former Special Representative For Ukraine negotiations who testified behind closed doors Thursday. The full document with the texts can be read here. But here are some of the most significant passages:

Volker (July 19th): “Had breakfast with Rudy this morning—teeing up call with Yermak Monday, Must have helped. Most (important) is for Zelensky to say that he will help investigation—and address any specific personnel issues—if there are any.”

Volker (July 25)” “Heard from White House assuming President Z convinces trump he will investigate / ‘get to the bottom of what happened’ in 2016, we will nail down date for visit to Washington. Good luck.”

Bill Taylor – U.S. Diplomat in Ukraine (August 30th): “Are we now saying that security assistance & WH meeting are conditioned on investigations?”

Taylor (Sept. 8th): “The nightmare is they give the interview and don’t get the security assistance. The Russians love it. (And I quit.)”

The Washington Post’s Philip Bump writes:

This is as explicit a quid pro quo as you can get: Promise to get to the bottom of events in 2016 — which could refer to either the hacking or to the firing of a Ukrainian prosecutor targeted by Biden — and you’ll get the validity that comes with a White House visit.