David Chipman, President Biden’s election to head the Alcohol, Tobacco, Firearms and Explosives Bureau, faced waning criticism from Republicans during his confirmation hearing Wednesday of his history of scathing comments on gun ownership.

Mr. Chipman, a two-decade veteran of the ATF who advised gun control groups, was selected in part because of his willingness to face an industry that has handcuffed the agency that enforces gun laws.

But his comments – including an interview last year in which he jokingly compared frantic gun purchases during the coronavirus pandemic to a zombie apocalypse – have been the subject of repeated questions from Republicans on the Senate Judiciary Committee.

“Many see it as a dedicated gun control advocate like David Chipman, who is in charge of ATF, a tobacco manager who is in charge of the Department of Health and Human Services, or Antifa, who is in charge of the Portland Police Department “said Senator Charles E. Grassley, Republican of Iowa and the senior committee member.

As the hearing began, news reports of a fatal shooting in San Jose, California began pinging on lawmakers’ phones. “I’m not lost that there is another mass shooting,” said Senator Amy Klobuchar, a Minnesota Democrat.

The National Rifle Association launched a coordinated campaign against Mr. Chipman’s nomination, citing his promises to regulate automatic weapons and his support for universal background checks.

The organization has effectively exercised a veto power over the appointment of stable leadership at the ATF and blocked several potential directors, including a conservative police union official who was tapped by President Donald J. Trump. The gun lobby has also waged a decades-long campaign to fight the ATF, fighting against fund increases and efforts to modernize their paper-based firearms tracking system.

Republicans said Mr. Chipman’s penchant for provocation made him an unacceptable choice in hopes of sinking his nomination, just as a story of inflammatory Twitter posts doomed Neera Tanden’s nomination, Mr. Biden’s first choice, to be his Head of household office.

Senator Mike Lee, Republican of Utah, barbecued Mr. Chipman for jokingly said in an interview last year that some first-time gun buyers were “preparing for end-time scenarios and zombie apocalypses.”

Mr Chipman, who appeared to be trying to avoid back and forth with Republicans, said the statements were “self-deprecating”. He also diverted questions about his advocacy of progressive politics by saying he considers himself a “policeman”.

Minutes later, after Texas Republican Senator Ted Cruz criticized him for calling for restrictions on AR-15-style rifles, Mr. Chipman thanked the Senator for telling me “me a Dr. Pepper offered ”.

Mr Biden elected Mr Chipman after a lobbying campaign by gun safety organizations led by former representative Gabrielle Giffords. For the past several years, Mr. Chipman has worked with groups led by Ms. Giffords and Michael R. Bloomberg, former Mayor of New York City, who also urged his selection.

The White House was initially reluctant to nominate anyone who would provoke such fierce opposition, but Mr Biden decided he had to take a risk after the mass murders in Atlanta and Boulder, White House officials said.

White House officials believe Mr Chipman has just enough votes – they estimate 50-52 – to overcome near-unanimous Republican opposition.

Two critical Democrats, Senators Joe Manchin III from West Virginia and Kyrsten Sinema from Arizona, have told Democratic leaders that if the hearings go well, they will likely vote for him. Two Republicans, Senators Susan Collins from Maine and Patrick J. Toomey from Pennsylvania, haven’t ruled out their support.