A proposal to store the nation’s nuclear waste deep under a mountain outside Las Vegas is breathing new life as one of its chief opponents, Senate Minority Leader Harry Reid, prepares to leave office.

Most Nevada politicians fiercely oppose the nearly three-decade-old push to deposit spent nuclear fuel and military waste at the Yucca Mountain Nuclear Waste Repository. Reid extracted a campaign promise to end the project from then-senator Barack Obama in 2008, and Obama’s Energy Department has withheld funding.

But Reid’s impending departure, and new cracks in the Nevada delegation’s historic opposition to the project, have supporters of Yucca mountain hoping for new life.

On Thursday, Rep. John Shimkus (R-Ill.) led a delegation of six members of Congress on a tour of the Yucca facility, five miles under the mountain. Shimkus, who chairs the House Energy and Commerce subcommittee with jurisdiction over the country’s nuclear energy policy, said Reid’s departure will change the dynamics.

“Being the majority leader of the Senate, now the minority leader, [Reid] has been challenging,” Shimkus said in an interview.

There are other signs that opposition to Yucca Mountain in Nevada is softening. In an editorial published last month in the Las Vegas Review-Journal, Rep. Cresent Hardy (R-Nev.), whose district includes the site, said it’s time for the Silver State to open a dialogue with the federal government over storage.

“Nevadans may never want nuclear waste stored inside Yucca Mountain. We certainly won’t let it be forced upon us,” Hardy wrote. “But if the dialogue changes and a discussion is had — and safety standards are overwhelmingly met — we should at least be up for an honest conversation.”

Advocates of Yucca saw Hardy’s op-ed as a crack in a previously-closed door.

“We were pleased with what I would say was his rational perspective,” said Marvin Fertel, president of the Nuclear Energy Institute, which favors storing waste at the facility.

Hardy and Rep. Mark Amodei (R-Nev.), who represented Yucca Mountain before the decennial redistricting process moved district boundaries in 2012, are both joining Shimkus on Thursday’s tour.

Reid’s departure hardly marks the end of Nevada’s opposition to Yucca. Sen. Dean Heller (R-Nev.) remains an ardent opponent; he said last week he still views the project as dead.

“I think the discussion has been had over the last 20 years, and I think it’s over. Yucca’s dead. We’re going to move on. I’ll continue to push that narrative just like Sen. Reid and Sen. [Richard] Bryan before me,” Heller told the Review-Journal. “Can I stop it? I will do everything in my capacity to do so.”

The delegation touring Thursday raised a minor dust-up between Shimkus and Heller, when the senator complained that a technical specialist from Nevada was not allowed to give the state’s perspective on the project. In a letter to Energy Secretary Ernest Moniz, whose department is hosting the delegation, Heller asked that the specialist be included. The Energy Department said it never heard of the request from Shimkus’s office.

“The Department has not received a request from the Subcommittee to include a participant representing the State of Nevada,” said Aoife McCarthy, an Energy spokeswoman. McCarthy said Energy “will fully consider and attempt to accommodate any additional requests” from Shimkus’s subcommittee.

As time goes by without a national depository for nuclear fuel, political pressure is building to find a site. Spent nuclear fuel is piling up in 34 states, and members from states, such as Illinois, Washington and Tennessee — which have significant reserves of used fuel at major nuclear energy facilities — want an answer. Five more states have large amounts of defense waste (Nevada officials point out that their state does not have any nuclear facilities, and thus doesn’t contribute to the stockpile of waste).

Shimkus pointed to the billions already invested in the Yucca Mountain project, and to a Nuclear Regulatory Commission study last year that concluded the site would not pose a risk, either to the surrounding area or to Las Vegas, 80 miles southeast.

“When you invest $15 billion in 30 years and all science points to, that was the right decision, for the sake of the taxpayers, regardless of the opposition, you have to move forward,” Shimkus said. “The world community is in agreement that long-term geological storage is the safest place to put spent nuclear fuel and defense waste.”

Shimkus said he will include language to fund Yucca Mountain in appropriations measures moving this year. Reid is just as likely to use his remaining influence in his final two years to strip that funding. But once Reid leaves office, Shimkus and Yucca supporters will press their case in a very different landscape.