George Conway and 15 other high-profile conservative lawyers argued Thursday that the House should begin an "expeditious" impeachment investigation into President Trump's interactions with foreign governments, reports the Washington Post.

Why it matters: The lawyers are targeting their joint letter at Republican lawmakers who — for the most part — have backed Trump's version of events, especially when it comes to his conversation with Ukrainian President Volodymyr Zelensky.

"We have not just a political candidate open to receiving foreign assistance to better his chances at winning an election, but a current president openly and privately calling on foreign governments to actively interfere in the most sacred of U.S. democratic processes, our elections."

The big picture: The group of lawyers is part of the Check and Balances coalition that Conway formed a last year to call out Trump when he acts in a manner they deem illegal and unconstitutional.

Many of the lawyers who've signed onto the letter have worked in previous Republican administrations.

Paul Rosenzweig, a lawyer in the George W. Bush administration, told the Post he thought the letter was too measured: "I would vote for impeachment, and I would vote for conviction and removal in the Senate as well."

Go deeper ... What we're reading: George Conway declares Trump mentally "unfit" for office