Asked why he felt it was necessary to warn Zelensky, Vindman told House impeachment investigators that it had become clear to him by March of this year that “there were public actors, non-governmental actors that were prompting the idea of investigations into 2016 Ukrainian interference.”

The revelation was jarring because it suggests that Zelensky was made aware by a U.S. official as early as May that there might be efforts to use him as a political pawn, shedding new light on recent reports that Zelensky raised concerns internally, with his staff, about the pressure he was feeling from Rudy Giuliani and other unofficial actors.

Vindman testified that he gave two pieces of advice during a bilateral meeting: “To be particularly cautious with regard to Russia and its desire to provoke Ukraine, and to stay out of U.S. domestic” politics.