Was it just us, or did everyone think Energy Secretary Steven Chu looked uncomfortable talking about Yucca Mountain last week?

During a congressional hearing Thursday, Sen. Patty Murray repeatedly pressed Chu to discuss the scientific basis for terminating the Nevada site as the nation's nuclear waste repository.

The Washington Democrat said she had read Chu's statements regarding the decision to withdraw Yucca Mountain's license application.

"What seems to be missing is the 'why,' " Murray said.

It's a trick question, of course. Everyone knows why the Obama administration wants to remove Yucca Mountain from consideration.

It fulfills a political promise Obama made to Nevada voters during his presidential campaign, and it helps Senate Majority Leader Harry Reid's chances for re-election. Republicans have a real shot at ousting Reid this year.

No wonder Chu seemed uneasy under Murray's repeated requests for the scientific reasons for abandoning Yucca Mountain.

Responding to Murray's questions without admitting the obvious required some rhetorical tap dancing.

"Other things, other knowledge and other conditions as they evolved made it (Yucca Mountain) increasingly not look like an ideal choice," Chu replied.

Ideal is an odd word to associate with nuclear waste disposal.

It's not the word we'd use to describe a political decision that threatens to strand about 70,000 tons of high-level nuclear wastes at Hanford and other sites across the country.

Recycling as much spent fuel possible for additional energy production, thereby drastically reducing the amount of wastes destined for a repository, would be a vast improvement over current nuclear waste policy.

But ideal? That's not going to happen.

Fiscal constraints, political realities and technical merit all influenced the selection of Yucca Mountain for permanent disposal of the nation's stockpile of spent reactor fuel and high-level defense wastes.

Not an ideal process, perhaps, but we've yet to hear a convincing reason to abandon Yucca Mountain.

The site combines congressional support, an investment of nearly $14 billion in public money and decades of safety and environmental studies.

The president's decision to appoint a blue ribbon panel on nuclear wastes to review alternatives would be all right if it didn't preclude Yucca Mountain.

But why take any alternative out of the running before the panel convenes? It looks like the administration is afraid an independent review might recommend the Nevada site after all.

If the panel is given the task of finding a safe, viable option -- forget about ideal -- Yucca Mountain could well rise to the top.

That would make it awfully tough for Obama to keep his political promises to Nevada. Avoiding that embarrassment has seemed like the only reason to take Yucca Mountain off the table.

Chu's testimony before Congress last week failed to provide any evidence to the contrary.