The House Judiciary Committee is taking the reins of the impeachment inquiry, holding its first hearing with testimony on the constitutional grounds for impeachment.
The committee, which will be responsible for drafting potential articles of impeachment, is hearing from four constitutional law experts: Noah Feldman, Pamela Karlan, Michael Gerhardt and Jonathan Turley, who is also a CBS News contributor.
Chairman Jerry Nadler said the president "directly and explicitly invited foreign interference in our elections."
"Never before in the history of the republic have we been forced to consider the conduct of a president who appears to have solicited personal political favors from a foreign government," Nadler said. "Never before has a president engaged in a course of conduct that included all of the acts that most concerned the framers."
Feldman, Karlan and Gerhardt were called to testify by the Democratic members, and Turley was called by the Republicans.
On Tuesday, the House Intelligence Committee voted to endorse a 300-page report written by the Democratic majority on President Trump's dealings with Ukraine, accusing the president of abuse of power.
The vote fell along party lines, with 13 Democrats voting to endorse the report and nine Republicans dissenting. The report was written by Democratic staffers on the House Intelligence, Foreign Affairs and Oversight Committees.
"This report chronicles a scheme by the president of the United States to coerce an ally, Ukraine, that is at war with an adversary, Russia, into doing the president's political dirty work," House Intelligence Committee Chairman Adam Schiff said on Capitol Hill.