Nick Clegg has given an interview to The House magazine in which he's questioned about the increasing possibility of a pre-emptive strike by Israel against Iran. Asked if Britain would participate in military action, he replies:
It depends entirely on what Iran's intentions are. I think of course you don't in a situation like this take any options off the table. When you are in a major stand off with a country which appears to have a sort of hostile intent on these issues, of course you don't do that. But equally we have been very very clear that we are straining every single sinew to resolve this through a combination of pressure and engagement.
His assertion that no options should be taken "off the table" is notable because unlike Labour and the Conservatives, the Lib Dems explicitly opposed military action in their election manifesto. The pledge read:
[W]e oppose military action against Iran and believe those calling for such action undermine the growing reform movement in Iran.
At the time, when foreign policy was far from most politicians' minds, Clegg probably thought little of the promise. But it could become a millstone around his neck. The Lib Dems, a party with a strong pacifist wing, would likely oppose any attack on Iran.
Clegg would probably argue that events have moved on since May 2010 or point out that the Lib Dems are in coalition. But at a time when he's pursuing a differentiation strategy in other areas, most Lib Dems will be dismayed by his equivocation.