Mitt Romney’s national security advisor Dan Senor caused a stir yesterday when he said the candidate would respect a decision by Israel to unilaterally strike at Iran’s nuclear facilities. This sent the Romney campaign into yet another round of damage control on this overseas tour.

But the bigger issue was a separate statement said by Senor and repeated by Romney in his speech in Jerusalem. Here’s what Senor had to say:

“So there are really two clocks — there is the clock determining the speed at which Iran is developing the capability and there is the clock that would preclude Israel from taking action. And so there is a range of these estimates around, but I think everyone understands — us officials and officials around the world — that we are dealing with an inevitability at the pace we’re going which is not far off.”

And here’s the excerpt from Romney’s speech:

We must not delude ourselves into thinking that containment is an option. We must lead the effort to prevent Iran from building and possessing nuclear weapons capability. We should employ any and all measures to dissuade the Iranian regime from its nuclear course, and it is our fervent hope that diplomatic and economic measures will do so. In the final analysis, of course, no option should be excluded. We recognize Israel’s right to defend itself, and that it is right for America to stand with you.

This has been a fairly consistent view from Romney – he claims that he first made this point at the Herzliya conference five years ago – but it departs from current practice. There’s a difference between preventing Iran from obtaining a nuclear weapon, and preventing them from a nuclear weapons “capability.” Preventing a capability means preventing uranium enrichment entirely, or preventing the existence of a nuclear program, even a civilian one, if it could be turned into a weapons program at some point. Iran could not have decided to launch a weapons program, but under this standard, if they have the capability, they would be subject to attack. Israeli Prime Minister Benjamin Netanyahu fell all over himself to agree with Romney on the “capability” point.

It’s a much lower bar for action, in line with the Israeli hardliner thinking but not the way US foreign policy has traditionally oriented itself outside of the neocon view. A capability threshold risks a military action because it’s completely subjective; you could argue that Iran has reached that threshold now.

Romney took pains to say this: “Because I’m on foreign soil, I don’t want to be creating new foreign policy for my country or in any way to distance myself from the foreign policy of our nation.” But he absolutely did distance himself from current foreign policy thinking. The subtle yet distinct shift to a nuclear weapons “capability” is a dangerous step forward into uncertain territory.