Mayor Bloomberg’s decision to confront New York’s two senators on their vote for a retreat in Iraq couldn’t be timelier, coming as it does at one of the most fraught moments in the entire war debate. His comments came at a press appearance yesterday, where he was asked about the vote in the Congress to set a date for withdrawal of troops from the Battle of Iraq. The mayor made a point of separating the issue of whether we should be fighting a war. “Let’s leave that aside,” he said, though he has, in the past, supported the war effort. “The issue here,” he said, “— we ask our young men and women to go over and to fight, and if you have a deadline knowing they’re pulling out, how can you expect them to defend this country? How can you expect them to go out and put their lives at risk? I just think that’s untenable and that this is not a responsible piece of legislation.”

The significance of the mayor’s remarks — aside from their logic and the notion that he understands that what our GIs are doing in Iraq is defending this country — is that it gives a glimpse of the kind of practical, common-sense approach the mayor is likely to take to the war debate. This isn’t an endorsement. Mayor Giuliani is taking a far more idealistic and impassioned position on the war. But it is a moment to suggest that the mayor will, if he runs, speak for a lot of people, in New York and beyond, who might not be as hawkish as the Republican front-runner but nonetheless see the mistake of the policy of fickleness among the Democrats.

It’s hard not to think that such talk, coming from a centrist like Mr. Bloomberg, puts Senator Clinton in an awkward position. The standard analysis would be that she is running to the left in the primaries with a scheme to tack back to the center after the nomination. Suddenly Mr. Bloomberg is holding out the prospect that when she tries to tack back to the center, she is going to find that the center has already been taken. It doesn’t lay a glove on President Bush or Mr. Giuliani, at least not at the moment, but it kind of fences off Mrs. Clinton.

One press appearance doesn’t make a campaign, and Mr. Bloomberg will have plenty of occasion either to waffle or to fill out his stance on the war. Meantime he’s taken a terrific first step, shrewdly calculated, one that will be read as dispiriting to our enemies and encouraging to our troops.