WASHINGTON (AP) — The White House will withdraw the nomination of a gun-control advocate to lead the Bureau of Alcohol, Tobacco, Firearms and Explosives after David Chipman ran into bipartisan opposition in the Senate, a person familiar with the decision said Thursday.

Chipman is a former federal agent and adviser at the gun control group Giffords. He won praise from advocates for his work pushing for greater regulation and enforcement on ghost guns, overhauling the background check system and moves to reduce the trafficking of illegal firearms.

But that same advocacy drew opposition from moderate Republicans such as Sens. Susan Collins of Maine and Lisa Murkowski of Alaska, as well as independent Sen. Angus King of Maine, dooming his prospects for confirmation in the 50-50 divided Senate.

Chipman’s nomination had stalled for months and he was widely seen as one of the administration’s most contentious nominees. The White House and top Democrats had been pushing to try to save his nomination for weeks but could not secure the necessary votes, with some Democrats saying privately they would not vote for him.

The White House declined to comment on the decision.

The person familiar with the decision was not authorized to publicly discuss the developments in Chipman's nomination and spoke on condition of anonymity.

The director’s position was made confirmable in 2006. Since then, only one nominee has made it successfully through what has become a politically fraught process mired in the overall gun debate.

Former U.S. Attorney B. Todd Jones was confirmed in 2013 but even then, it took six months. Jones was acting director when then-President Barack Obama nominated him in January 2013. He had been acting director since 2011 after his predecessor resigned amid a scandal over an ATF gun investigation.

The withdrawal of the nomination leaves the chief firearm and explosive investigation agency without a confirmed leader at a time when the Biden Administration has made gun violence enforcement a priority, but with limited resources.

Earlier this year Biden announced a series of executive actions aimed at what he called “epidemic and an international embarrassment” of gun violence in America.

The actions were a fraction of the ambitious gun control agenda he proposed as a candidate and underscored his limited power to act alone on guns with difficult politics impeding legislative action on Capitol Hill.

Biden has urged Congress to tackle a number of issues, expanding background checks and banning assault weapons and high-capacity magazines.

But with an evenly-divided Senate — and any gun control legislation requiring 60 votes to pass — Democrats would have to keep every member of their narrow majority on board while adding 10 Republicans.

A person with knowledge of discussions with Chipman said he had been offered a position at Justice but turned it down.