The idea of using nuclear weapons in Afghanistan or against terrorists hasn't really been under discussion, but what about the question of using bunker-busting nuclear missiles to target Iran's nuclear weapons program?  In other words, for a preemptive nuclear attack on Iran?

There was a lot of discussion a few months ago about whether conventional weapons could be used to penetrate the bunkers Iran has been using for its nuclear program.  Interestingly, in their public positions, none of the candidates (including Obama) offered at the time to rule out such a strike, although Obama did reject the Bush administration's proposal to invest in research for a new generation of low-yield bunker-busting nuclear weapons.

Per an article on the Huffington Post:

As early as August 13, 2005, Bush, in Jerusalem, was asked what would happen if diplomacy failed to persuade Iran to halt its nuclear program. Bush replied, "All options are on the table." On April 18, the day after the appearance of Seymour Hersh's New Yorker report on the administration's preparations for a nuclear war against Iran, President Bush held a news conference. He was asked,

"Sir, when you talk about Iran, and you talk about how you have diplomatic efforts, you also say all options are on the table. Does that include the possibility of a nuclear strike? Is that something that your administration will plan for?"

He replied,

"All options are on the table."

The President never actually said the forbidden words "nuclear war," but he appeared to tacitly acknowledge the preparations -- without further discussion.

Vice-President Dick Cheney, speaking in Australia last week, backed up the President.

"We worked with the European community and the United Nations to put together a set of policies to persuade the Iranians to give up their aspirations and resolve the matter peacefully, and that is still our preference. But I've also made the point, and the president has made the point, that all options are on the table."

Republican Presidential Candidate John McCain, on FOX News August 14, 2005, said the same.

"For us to say that the Iranians can do whatever they want to do and we won't under any circumstances exercise a military option would be for them to have a license to do whatever they want to do ... So I think the president's comment that we won't take anything off the table was entirely appropriate."

But it's not just Republicans. Democratic Presidential candidate John Edwards, in a speech in Herzliyah, Israel, echoed Bush.

"To ensure that Iran never gets nuclear weapons, we need to keep ALL options on the table. Let me reiterate - ALL options must remain on the table."

Although, Edwards has said, when asked about this statement, that he prefers peaceful solutions and direct negotiations with Iran, he has nonetheless repeated the "all options on the table" position -- making clear that he would consider starting a preventive nuclear war, but without using the fateful words.

Hillary Clinton, at an AIPAC dinner in NY, said,

"We cannot, we should not, we must not, permit Iran to build or acquire nuclear weapons, and in dealing with this threat, as I have said for a very long time, no option can be taken off the table."

Translation: Nuclear weapons can be used to prevent the spread of nuclear weapons.

Barack Obama, asked on 60 Minutes about using military force to prevent Iran from developing nuclear weapons, began a discussion of his preference for diplomacy by responding, "I think we should keep all options on the table."

The article, actually from George Lakoff, charges that Democrats have allowed the Bush administration to get away with a loose euphemism.  They have been able to rule nothing out and leave out the possibility of a preemptive nuclear strike without the public having the chance to engage in a genuine debate about its wisdom.