Former New York mayor Rudy Giuliani appeared Monday as the first witness in his own attorney misconduct hearing, but the proceedings quickly grew combative as the opposing counsel dinged Giuliani for failing to answer straightforward questions and frequently meandering off course.

The ethics case, brought by the Washington, DC Bar's Office of Disciplinary Counsel, zeroes in on Giuliani's effort to overturn the 2020 election results in Pennsylvania when he was then-President Donald Trump's personal attorney. Specifically, the ODC alleges that the former New York mayor filed a "frivolous" lawsuit seeking to nullify Pennsylvania's presidential election results, despite the fact that there was "no factual or legal basis" for Giuliani's claims of widespread voter fraud.

By filing the lawsuit, the ODC said, Giuliani violated the Pennsylvania Rules of Professional Conduct and "engaged in conduct prejudicial to the administration of justice."

On Monday, disciplinary counsel Hamilton Fox said in his opening arguments that Giuliani "weaponized his law license" in an effort to undermine the Constitution.

"Mr. Giuliani was responsible for filing a frivolous action asking a court in Pennsylvania to deny millions of people the right to vote," Fox said during the virtual hearing.

Fox grew increasingly frustrated with Giuliani as the proceedings went on. At one point, he was trying to get more details from Giuliani about his role in litigating the Pennsylvania case, but the former mayor repeatedly veered off course and started airing nonsense allegations of voter fraud in other states.

"Mr. Giuliani, I am trying to find out what your role was in writing — in drafting — the initial complaint in Pennsylvania," Fox said. "I'm asking you what time it is, and you're telling me how to make a watch."

"Well, you know, I really do think you should let me answer the question, so I can get the context in which I was operating," Giuliani said. "So you don't create the false impression that all my time and attention was given to one matter when that was not the case."

Later in the proceedings, Giuliani was again reminded that he was there to answer questions as a witness when he started opining on a 5-2 Pennsylvania Supreme Court ruling about voting procedures in the state.

"I recall this very, very clearly," Giuliani said of the ruling. "This is a very debatable opinion."

Fox ignored Giuliani and pointed out that the ruling held that election observers "be permitted to remain in the room where the ballots are being counted."

"So you would agree that my position is reasonable, since it was the same position as ... the dissenters," Giuliani said. "It was hardly —"

Fox then interjected, saying, "Mr. Giuliani, I ask the questions."

Robert Bernius, a retired lawyer who presided over the hearings, also tried multiple times to rein Giuliani in.

"Mr. Giuliani, I understand your frustration, but this is not the point at which you should argue your claims," he said. "Just answer the questions. Thank you."

Earlier in the day, Bernius interrupted another long-winded rant from Giuliani to remind him that he was testifying as a "witness."

The former mayor then said that he had been "persecuted for three or more years" and that his actions were taken out of context.

"You've been a trial lawyer for a long time, and you understand how the process works," Bernius said. "The process is regularized."