During her time to ask questions, Rep. Alexandria Ocasio-Cortez, D-N.Y., said the allegations are "extremely serious," but called the hearing an "embarrassment."

She established that none of the four witnesses can give any firsthand witness account of any crimes committed by the president.

"This is an embarrassment. It is an embarrassment to the time and people of this country," she said.

Rep. Glenn Grothman, R-Wis., followed by saying he was concerned about the "seriousness of the allegations."

"We have all sorts of smoke, maybe not fire," he said. "It deserves a strong response from this body."

Rep. Shontel Brown, D-Ohio, asked Democratic witness Michael Gerhardt what he believes is the "primary flaw" in the Republican claims about President Biden.

"Well, I suppose I can say a lot. The problem is the dots are not connected," Gerhardt replied. "The name repeated most often is Hunter Biden, not President Biden. And the point of an impeachment inquiry is not about a president's son, it has to be about the president himself and I don't think those dots connected. Lots of assumptions and accusations, not evidence."

Rep. Jim Jordan, R-Ohio, chairman of the House Judiciary Committee, called testimony from Hunter Biden's former business partner, Devin Archer, "the most telling evidence" of the president's potential involvement in an "influence-peddling scheme."

Jordan said that a Ukrainian prosecutor investigating a Ukrainian company tied to Hunter Biden's was fired after Hunter Biden received a request from Burisma's top executive and then called his father, who "leveraged $1 billion of American tax money" to get the prosecutor fired.

But a review of Archer's testimony, detailed in a publicly-released transcript, shows that Jordan left out key parts of Archer's testimony and mischaracterized other parts of it.

Among other things, Archer said the request from Burisma's top executive wasn't specific to the prosecutor's firing, and he wasn't even sure that Hunter Biden called his father after getting the request.

--ABC News' Mike Levine and Luc Bruggeman

Democrats again tried to force a vote on subpoenaing Trump ally Rudy Giuliani over his alleged efforts to dig up dirt on the Biden family's business dealings in Ukraine and Biden's actions as vice president. Republicans were able to successfully kill the motion.

Chairman Comer attempted to dispense of the motion with voice vote but Democratic Rep. Jamie Raskin pushed for a recorded vote. It failed 20-18.

"Where in the world in Rudy Giuliani?" Rep. Kwesi Mfume, D-Md., bellowed, holding up a piece of paper that read the same.

Jonathan Turley, a constitutional law professor called by Republicans to testify, said he believes it's a "best practice" to hold a full House vote to open an impeachment inquiry.

"It brings solemnity and weight of the decision," Turley told Democratic Rep. Ro Khanna.

Republicans have yet to hold a formal vote. House Speaker Kevin McCarthy, despite previously stating he'd hold a floor vote, unilaterally ordered the inquiry on Sept. 12. At the time, it appeared he lacked the support from his caucus for any such measure to pass.

When pressed by Khanna if he'd advise McCarthy to change course, Turley responded: "I always said I thought it was best practice."

Whether or not a House vote is needed to launch an impeachment inquiry -- as has been tradition -- is a point of contention. Democrats have pointed to a Trump-era Office of Legal Counsel memo that stated impeachment inquiries must have sign off from the House. Meanwhile, Republicans highlighted a 2019 federal district judge decision that the Democrats were legally engaged an impeachment inquiry into former President Donald Trump despite no vote being held at the time (Democrats later did vote to formalize the impeachment inquiry).