WASHINGTON - Ever since President Barack Obama promised to significantly scale back the Yucca Mountain budget this year, the question has been a simple one: Now what?
Sometimes the question comes as a genuine line of inquiry about the future of nuclear waste. At other times it is loaded with incredulity.
Either way, Obama's proposal has caused a phenomenal shift in thinking that would have seemed unbelievable just a few months ago.
Gone are the repeated arguments that federal law requires construction of a nuclear waste storage dump at Yucca Mountain and the extended debates over science and safety. Yes, lawsuits seeking to hold the government accountable for its promise to handle the waste are continuing and many Yucca Mountain supporters say they will fight on. But with Obama saying Yucca Mountain will not be developed on his watch, those long-standing issues seem of less importance.
On Wednesday a Senate energy committee hearing on nuclear power offered a window onto the new day that has arrived in Washington.
"If Yucca Mountain were taken off-line, what's Plan B?" said Sen. Mark Udall, the Colorado Democrat.
At the witness table, Dale Klein, chairman of the Nuclear Regulatory Commission, offered the solution that has been before Congress for years. The waste will stay where it now sits, Klein explained. Spent nuclear fuel pellets will be stored safely in containers at utility companies' nuclear power sites across the nation for the next 100 years or more.
"Dry cast storage is Plan B," Klein said.
Moments later Sen. John McCain, the former Republican presidential candidate, asked the same question. McCain is a Yucca Mountain project supporter who has been reluctant to let Obama win this battle.
"What are you counting on for an alternative?" McCain said, apparently aware of the answer.
"For the interim, dry cast storage," Klein said.
"Dry cast storage," McCain repeated, incredulous. "Spent nuclear fuel sitting in pools at power plants all over America - is that what you're talking about?"
But even McCain, perhaps the most prominent Yucca Mountain supporter on the Hill, could see the writing on the wall. He fast-forwarded to his point.
"Any national security expert - amateur - would tell you: You need one place to store it, and that's not going to happen now because the administration has declared that."
The way the conversation turned was a public reminder that elections matter. Just a few years ago the Bush administration was trying to bolster Yucca Mountain. Bush championed a nuclear energy resurgence as a means of obtaining carbon-free energy.
But the story line in Washington suddenly changed - as if a rail yard worker flipped a switch and the train jumped to a new track.
Obama and Sen. Harry Reid, the majority leader, are seen by many as an essentially unstoppable alliance in killing the Yucca Mountain plan.
On paper, many past supporters of Yucca remain strong backers, despite the project's fiscal, political and scientific setbacks.
Yet as one Yucca supporter put it Wednesday, it has been no secret where the Yucca debate is going. Even the utility companies had started decoupling the waste issue from efforts to spur a nuclear renaissance, saying they no longer factored Yucca Mountain into their plans to develop new plants.
Klein said the Nuclear Regulatory Commission is considering extending on-site storage to as much as 120 years.
"Yucca has been an interesting sort of thing to be out there," Sen. Bob Corker, the Tennessee Republican, said this month. "Hopefully there's another solution they're focused on that allows us to use the waste in an appropriate way versus putting it in concrete."
What the Obama administration plans to do with the spent fuel in the long term remains an unanswered question that makes everyone involved uneasy.
Will a willing host community be chosen for a centralized waste storage site? Will the nation embark on a mission to recycle the waste as other countries do, even though many scientists believe the technology remains decades from being financially viable?
The nuclear industry and its supporters most want an assurance that nuclear revival remains on track. At stake are billions of dollars in federal support.
Karen Harbert, president and chief executive of the Institute for 21st Century Energy at the U.S. Chamber of Commerce, issued a statement Wednesday saying that "while the Institute supports storing waste at Yucca Mountain as required by law ... the operation of Yucca Mountain is in no way a technical or regulatory prerequisite to the growth of nuclear energy in America."
Obama's administration is convening an industry-supported committee to consider disposal options. Reid and Republican Sen. John Ensign have a similar proposal in a bill before Congress.
Sen. Lisa Murkowski of Alaska, the top Republican on the Senate Energy and Natural Resources Committee, expressed her frustration Wednesday at the new order.
"So far, this administration has sought to kill Yucca Mountain as a long-term repository for spent nuclear fuel without yet providing alternatives," she said. Where nuclear stands with the administration, she said, "is a bit of a mystery to me."