The complaint alleged that Trump used the "power of his office to solicit interference" from a foreign country in the 2020 election -- and that White House officials subsequently tried to "lock down" records of that phone call.
"He sought to pressure the Ukrainian leader, to take action to help the president's 2020 reelection bid. There it is, that line. He did what he's been accused of doing. It's impeachable," said Matthews, reading from the complaint, along with fellow MSNBC hosts Joe Scarborough and Mika Brzezinski.
"It's a moment, and Democrats, if they've got brains, and any political savvy– will grab this moment. No more hearings, no more subpoenas, no more contempt citations... they've got him."
The rough transcript of the July call between Trump and Ukrainian President Volodymyr Zelensky was released a day earlier by the White House. It confirmed that Trump sought an investigation from Ukraine into the Biden family, though it did not show the president explicitly leveraging U.S. aid as had initially been suggested in some media reports.
But the whistleblower complaint, released by the Democrat-led House Intelligence Committee ahead of testimony from Acting Director of National Intelligence Joseph Maguire, goes further, though it is not a first-hand account of the call.
The whistleblower, who remains anonymous, says in the complaint that White House officials who heard the call were "deeply disturbed" by it, and that White House lawyers discussed how to handle the call "because of the likelihood, in the officials' retelling, that they had witnessed the president abuse his office for personal gain."
"In the days following the phone call, I learned from multiple U.S. officials that senior White House officials had intervened to 'lock down' all records of the phone call, especially the official word-for-word transcript of the call that was produced -- as is customary -- by the White House Situation Room," the complaint says.
Fox News' Ronn Blitzer contributed to this report.