A lawyer who tried to help President Trump overturn the 2020 election, John Eastman, is now fielding a barrage of questions about whether he knew at the time that cases of “voter fraud” he cited in his legal efforts were specious or fabricated.

Mr. Eastman was the lawyer at the heart of Mr. Trump’s attempts to overturn the election and an architect of the flurry of lawsuits the former president’s team filed frantically after the 2020 election in their efforts to keep him in power. Mr. Eastman is now fighting disbarment in California, where he lives and practices law. 

Mr. Eastman is also under scrutiny by Special Counsel Jack Smith, who’s seized the lawyer’s cellphone, a move that he is currently fighting in court. Mr. Smith is also trying to seize the phone records of a conservative Pennsylvania congressman, Scott Perry, who discussed pro-Trump legal strategies with Mr. Eastman in the aftermath of the 2020 election.

Mr. Eastman’s legal theories supporting Mr. Trump’s re-election also took a major blow this week when the Supreme Court ruled, in Moore v. Harper, that state legislatures do not have sole authority to establish federal election laws.

As for his ordeal before the California state bar, Mr. Eastman was charged by the bar on January 23 with 11 counts of various offenses alleging he “engaged in a course of conduct to plan, promote, and assist then-President Trump in executing a strategy, unsupported by facts or law, to overturn the legitimate results of the 2020 presidential election by obstructing the count of electoral votes of certain states.”

The California bar’s chief trial counsel, George Cardona, said in a statement that the charges stemmed from Mr. Eastman’s “moral turpitude” during his time advising the then-president. 

“There is nothing more sacrosanct to our American democracy than free and fair elections and the peaceful transfer of power,” Mr. Cardona wrote. “For California attorneys, adherence to the U.S. and California Constitutions is their highest legal duty. The Notice of Disciplinary Charges alleges that Mr. Eastman violated this duty in furtherance of an attempt to usurp the will of the American people and overturn election results for the highest office in the land.”

Thursday’s hearing — the fourth day in what is an eight-day proceeding that began last week — focused mainly on the lawsuits Mr. Eastman was party to on behalf of the former president in the days and weeks following the 2020 election. 

The first case Mr. Eastman was questioned about was Texas v. Pennsylvania, which was brought before the Supreme Court by the state of Texas and sought to block the certification of Pennsylvania’s electoral votes for President Biden. It received amicus briefs from 17 Republican state attorneys general and 126 GOP members of Congress. 

Mr. Eastman, while not an official signatory to the lawsuit, said he worked with the Texas state attorney general, Ken Paxton, and Mr. Trump to bring the matter before the high court. The lawyers questioning Mr. Eastman in California on Thursday asked if it was true that the election was stolen, as was claimed in Texas’s legal briefing to the justices. 

“It says what it says,” Mr. Eastman responded curtly. “Something is deeply amiss.” He went on to claim that “illegal conduct by election officials” allowed “illegal ballots” to change the outcome of what otherwise would have been a victory for Mr. Trump. 

Mr. Eastman said shortly after that he “could not prove” voter fraud “but could not disprove it either.” He said he never made claims that voters themselves acted illegally in any legal brief or any advice he offered to Mr. Trump in private. 

“Election fraud,” Mr. Eastman explained, “is not the same as voter fraud.” State courts and Democratic election officials across the country did commit election fraud, he claimed, defining election fraud as “fraud-inducing changes” to the voting processes of state and local governments.

Some examples he offers are the suspension of signature verification and the deployment of ballot drop boxes, both of which were used by multiple states to ensure greater voter access during the Covid pandemic. 

Mr. Eastman was also challenged by state bar lawyers about the so-called expert witnesses he deployed in several court cases. One such “expert” was Republican operative Matthew Braynard, whose only experience was working to register Republican voters in the wake of the 2016 election and serving as data director for Mr. Trump’s first presidential campaign.

His academic credentials include a bachelor’s degree from George Washington University and a master of fine arts degree in creative writing from Columbia University’s highly regarded program.

When pressed on whether it was appropriate to include Mr. Braynard as an expert witness in his legal briefs, Mr. Eastman dodged the question several times. “I’m just going off his experience,” he told state bar lawyers. 

He was then shown a legal brief filed by a professor of political science at the Massachusetts Institute of Technology who claimed Mr. Trump’s accusations of fraud were baseless. Mr. Eastman was asked if he would trust Mr. Braynard over the professor, who has decades of experience conducting research on American elections. 

At one point, the presiding judge, Yvette Roland, chastised Mr. Eastland for avoiding the question after he said multiple times that the professor’s academic experience matched the practical experience of Mr. Braynard. 

State bar lawyers have been consistently hammering Mr. Eastman for his alleged lack of professionalism in filing affidavits from witnesses who would later turn out to have no information about fraud. 

At one point, lawyers claimed that Mr. Eastman unscrupulously filed an affidavit from a Pennsylvania truck driver named Jesse Morgan who claimed he’d unsuspectingly driven “hundreds of thousands” of suspicious mail-in ballots from New York to the key swing state of Pennsylvania ahead of election day — a claim that was later proven to be untrue. 

It later turned out that Mr. Morgan was also an amateur “ghost hunter” who claimed to be persistently haunted by ghosts, assertions he made in an appearance on the Travel Channel. The York Daily Record also reported that Mr. Morgan had “a lengthy history of drug abuse, mental health issues, and allegations of domestic violence.”

Mr. Eastman’s antagonists at the California state bar claim he irresponsibly “did no research to assess [Mr. Morgan’s] credibility” before filing his affidavit. 

If Mr. Eastman is disbarred and banned from practicing law in the state of California, he will be one of the first members of the inner circle that planned the election decertification to face professional repercussions. Mayor Giuliani had his law licenses temporarily suspended in both New York and the District of Columbia following the January 6, 2021, attack on the Capitol. 

The state bar court has said the trial proceedings against Mr. Eastman should end by early July. 

His disbarment issues could be the least of his troubles if Mr. Smith indicts him alongside Mr. Trump for election interference, much as he indicted Mr. Trump’s valet, Waltine Nauta Jr., in the Mar-a-Lago documents case.