Cameron's first war?
It happens to every prime minister.
There comes a moment when they take a decision which could lead to the loss of British servicemen and women's lives in military action.
Little noticed, it happened today in David Cameron's Commons statement on Libya when he said:
"We do not in any way rule out the use of military assets. We must not tolerate this regime using military force against its own people. In that context I have asked the Ministry of Defence and the Chief of the Defence Staff to work with our allies on plans for a military no-fly zone."
Now Downing Street are stressing that they are just examining options; that a no-fly zone would require international support; that it could operate in a variety of different ways - covering part of, rather than the whole of, Libya's massive territory, involving Nato or some other alliance of nations and with or without aggressive rules of engagement allowing for Libyan planes to be shot down.
HMS Cumberland evacuates British and foreign nationals from Benghazi
They are pointing out that it is at the end of a long list of other non-military ways to put pressure on the Gaddafi regime. They explain that the reason they can talk now about an idea they poured cold water on a few days ago is because most British citizens are now safely out of Libya.
Clearly, this may be little more than sabre-rattling by a prime minister determined to look on the front foot this week after being on the back one for much of last week.
However, the man who was once a sceptic about Tony Blair's liberal interventionism and who stressed that military action should always be in the British national interest has just made clear that he's prepared to contemplate the loss of British lives to save lives in Libya.
If it happened - and, of course, that remains a big "if" - Libya would be Cameron's first war. The military decisions he took before today all concerned the war he inherited in Afghanistan.