At his press conference this afternoon, President Obama was asked to respond to Mitt Romney’s number one applause line on Iran: If Obama is reelected, Iran will get a nuclear bomb. The answer, in some ways, contained echoes of the 2008 Obama.

Obama replied that intelligence officials still believe that there’s a “window of opportunity where this can still be resolved diplomatically.” He then accused rivals of a reckless and casual approach to momentous decisions about war and national security:

What’s said on the campaign trail, you know, those folks don’t have a lot of responsibilities. They’re not commander in chief. And when I see the casualness with which some of these folks talk about war, I’m reminded of the costs involved in war. I’m reminded of the decision that I have to make, in terms of sending our young men and women into battle, and the impacts that has on their lives, the impact it has on our national security, the impact it has on our economy.

This is not a game. And there’s nothing casual about it. And, you know, when I see some of these folks who had a lot of bluster and a lot of big talk, but when you actually ask them, specifically, what they would do, it turns out they repeat the things that we’ve been doing over the last three years. It indicates to me that that’s more about politics than actually trying to solve a difficult problem.

Now, the one thing that we have not done, is we haven’t launched a war. If some of these folks think that it’s time to launch a war, they should say so. And they should explain to the American people exactly why they would do that and what the consequences would be. Everything else is just talk.

Now, opponents of Obama’s escalation in Afghanistan will ask whether he really was accurate in his cost-benefit assessment of that decision. But on the substance of Obama’s response today, which is that for all their bluster, there isn’t much difference between the GOP candidates’ policies towards Iran and his own, experts happen to agree with Obama.

Obama’s insistence that there’s still a window for peaceful resolution, and that the warmongering from the GOP could prove counterproductive, are both in some ways reminiscent of 2008. Obama was pilloried as weak on national security matters both by Hillary Clinton, who called him “naive” on Iran, and by John McCain, who all but painted him as a terrorist sympathizer. In responding to both, Obama proceeded from the assumption that he could win an argument over national security by unabashedly making the case for negotiating with enemies and against mindless militarism. He gambled that voters would ultimately reject the assumption that the former constitutes automatic weakness and the latter constitutes automatic strength.

No question: Since then, in some ways, Obama has capitulated to the hawkish worldview, on civil liberties and other aspects of the war on terror. But on Iran, he seems to be gambling that he can win the argument in the public mind by arguing against hollow, hawkish chest-thumping, by pointing out that wars have consequences, and by lampooning his opponents’ casual and simplistic approach to these questions, even as he’s the one making the difficult decisions about them. The message: I’m commander in chief, and you’re just playing one on TV. Just as in 2008, the outcome of this argument will hinge on the public’s decision as to what really constitutes weakness, and what really constitutes strength.