Democrats' witnesses at the House Judiciary Committee's first impeachment hearing testified Wednesday that President Donald Trump committed impeachable offenses, with one witness going farther to say that his dealings with Ukraine "are worse than the misconduct of any prior president."

The House Judiciary Committee took the reins of Democrats' impeachment inquiry with its first public hearing focused on discussing the "historical and constitutional basis of impeachment" as well as the definition of terms like "high crimes and misdemeanors." Four constitutional scholars and law school professors were called as witnesses.

"The president's serious misconduct, including bribery, soliciting a personal favor from a foreign leader in exchange for his exercise of power and obstructing justice and Congress are worse than the misconduct of any prior president, including what previous presidents who faced impeachment have done or been accused of doing," Michael Gerhardt, a professor at the University of North Carolina Law School, said in his opening statement.

Gerhardt's claim that Trump committed more severe offenses than past presidents who faced impeachment echo similar statements made by House Speaker Nancy Pelosi of California and House Intelligence Committee Chairman Adam Schiff of California. Pelosi has argued that Trump's actions were "so much worse" than that of former President Richard Nixon, who resigned from office before the House voted on impeachment.

Democrats are investigating whether Trump abused his office by pushing Ukraine's president to make a public statement about opening investigations into the 2016 election and former vice president Joe Biden and used a White House meeting and congressionally approved military aid as leverage. Schiff's report on the impeachment inquiry released Tuesday concluded that Trump "undermined" national security through a pressure campaign that involved a foreign country helping his own reelection bid.

"Both of these acts constitute high crimes and misdemeanors impeachable under the Constitution," said Noah Feldman, a professor at Harvard Law School who was also called to testify by Democrats. "By freezing aid to Ukraine and by dangling the promise of a White House visit, the president was corruptly using the powers of the presidency for personal political gain."

But not all witnesses believe that Trump committed impeachable offenses. Jonathan Turley, a professor at George Washington University Law School who is Republicans' lone witness, testified that pursuing impeachment "with the thinnest evidentiary record" would set a "dangerous" precedent.

"One can oppose President Trump's policies or actions but still conclude that the current legal case for impeachment is not just woefully inadequate, but in some respects, dangerous as the basis for the impeachment of an American president," Turley said in his opening statement.

Turley noted that he doesn't support Trump and has been openly critical of him, but added that his views "are irrelevant to his testimony" and the same standard should be applied to members on their future impeachment votes.