In fact, the idea behind Iraq Moratorium was never to "escalate" in the manner suggested. No material the organization's produced suggests so, anyway. (Indeed, it originally suggested things like wearing black arm bands.) The point, rather, is to engage the majority of people who are privately antiwar but don't demonstrate to do so.

The war will end when there's a serious threat of people serving certain roles in society refusing to serve or even transcending them as a means of resisting the war -- when soldiers refuse to fight, for instance. As I pointed out in response to Mike, this is not the kind of resistance that can be built overnight.

You vandalize a recruiting station. So what? At best you'll do some negligible damage -- do you really think the best-funded military in the world will have trouble replacing a window? More likely, though, you'll provide an excuse for increased repression and possibly turn off some potentially sympathetic people.

Now, if a whole community were to mobilize to shut down a recruiting station -- that's something much different, and very desirable. But there's absolutely no evidence that "propaganda of the deed" would encourage this sort of mobilization. There's a good chance of it making it look like a fringe cause, though.