A bitterly divided U.S. Senate panel deadlocked Thursday on President Joe Biden’s pick to oversee vast government-owned lands in the West, as Democrats stood united behind a nominee whose credibility was assailed by Republicans over her links to a 1989 environmental sabotage case.

The 10-10 tie in the Senate Energy and Natural Resources Committee sets up a floor vote on the nomination of Tracy Stone-Manning. It would take every Senate Republican plus at least one Democratic lawmaker to block her confirmation in the evenly divided chamber.

At stake is the leadership of the Interior Department's Bureau of Land Management, which oversees energy production, recreation and other activities across almost a quarter-billion acres of public lands, primarily in the West.

Tracy Stone-Manning listens during a confirmation hearing for her to be the director of the Bureau of Land Management, during a hearing of the Senate Energy and National Resources Committee on Capitol Hill, on June 8.

Tracy Stone-Manning listens during a confirmation hearing for her to be the director of the Bureau of Land Management, during a hearing of the Senate Energy and National Resources Committee on Capitol Hill, on June 8. (AP)

STONE-MANNING MAY HAVE VIOLATED ETHICS RULES, FEDERAL LAW WITH SCRUTINIZED 2008 PERSONAL LOAN

Stone-Manning was a top aide to former Montana Democratic Gov. Steve Bullock and most recently worked as a vice president at the National Wildlife Federation. Her advocacy for land preservation contrasts sharply with the land bureau's priorities under former President Donald Trump, who sped up oil and gas drilling approvals and sought to open up new lands to development.

Democratic Sen. Maria Cantwell of Washington state said fierce opposition to Stone-Manning among Republicans was rooted in her potential to bring change to the agency.

"This is over-the-top opposition," Cantwell said. "What is really on trial here is the future of America's public lands... oil, gas, coal, mineral extraction."

Republican lawmakers focused on Stone-Manning's links to the 1989 sabotage of a timber sale on Idaho's Clearwater National Forest, calling her an "ecoterrorist" unfit to oversee the land bureau. She was a 23-year-old environmental studies graduate student at the time at the University of Montana.

Two of Stone-Manning’s friends were convicted more than four years later of inserting metal spikes into trees, which makes it dangerous to cut them down. She received immunity from prosecutors and testified against them.

WHY DID THE AIR QUALITY IN THESE STATES PLUMMET?

She was never charged with any crimes.

Stone-Manning acknowledged retyping and sending a letter on behalf of one of the men convicted that warned authorities not to log in the sabotaged area. She didn't come forward until the criminal case was prosecuted several years later, and has said she was fearful of one of the defendants.

A former investigator for the Forest Service alleged last week that Stone-Manning was a target of the criminal investigation and helped plan the tree spiking. Others involved in the case, including the lead prosecutor, have disputed that characterization.

"This wasn't a mild offense in which she conspired," said Utah Republican Sen. Mike Lee. "People are hurt and killed by this kind of behavior."

Energy Committee Chairman Sen. Joe Manchin, D-W.Va., said he closely reviewed the case and found no evidence Stone-Manning was directly involved or committed any crime. He said the decades she spent in public service and environmental advocacy work made Stone-Manning a good choice for the bureau.

"I think of Tracy Stone-Manning being a youthful sympathizer for the environment," said Manchin, whose reputation as a moderate made his vote closely watched. "There's no proof that she's guilty of any of these things we've been talking about."

Republican lawmakers sought to dramatize Stone-Manning’s involvement by holding up metal spikes similar to the ones used in the 1989 sabotage during Thursday’s hearing.

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Idaho Republican Sen. James Risch referred to her as an "attempted murderer" because of the potential for the spikes to harm loggers. The remark drew a sharp rebuke from New Mexico Democratic Sen. Martin Heinrich, who said he was disgusted by Republican "lies" and attempts to besmirch Stone-Manning.

Majority Leader Chuck Schumer, D-N.Y., said Thursday he would call a vote on her nomination before the full Senate, where Vice President Kamala Harris could break a tie for confirmation.