I mentioned this yesterday. But it really deserves to be pointed out at more length that the new Obama campaign ad — which is running in six swing states — actually hits Mitt Romney for favoring an increase in defense spending, which isn’t an attack you often hear Dems making:

The ad says:

You watched and worried. Two wars. Tax cuts for millionaires. Debt piled up. And now we face a choice. Mitt Romney’s plan? A new $250,000 tax cut for millionaires. Increase military spending. Adding trillions to the deficit. Or President Obama’s plan: a balanced approach. Four trillion in deficit reduction. Millionaires pay a little more.

When is the last time a Democrat attacked a Republican for advocating an increase in defense spending?

This says a good deal about what the Obama team thinks about the state of public opinion right now. The ad’s goal is to associate Romney directly with George W. Bush — specifically, with the nexus of Bush adventurism abroad and the Bush deficit — without mentioning Bush’s name. The ad is about fiscal policy, but it’s also meant to suggest that Romney would continue Bush’s approach to foreign policy, and that we can’t afford to go that route again. The calculation seems to be that the war weariness of the American public — and the public’s awareness of the role of Bush’s wars in driving up the deficit — make it politically safe, or even a potential winner, to call out Romney’s proposed increase in defense spending as fiscally reckless.

The Obama team’s thinking seems to be that the public is open to an argument against prioritizing defense spending in lean times, particularly if it would mean cutbacks to other priorities. A CBS/NYT poll from February found that when forced to choose between cutting defense, Medicare, or Social Security, a majority, 52 percent, picked defense. Gallup has found the public consistently thinks we spend too much on defense, rather than too little. William Saletan compiles more polling evidence along these lines right here.

For a long time, Dems seemed to operate from the default position that even if the public doesn’t necessarily favor increased defense spending, they couldn’t risk getting into a fight over it with Republicans because it would play to public perceptions of Dems as weak on national security in a broader sense. But this Obama ad is directly taking on Romney’s proposal to increase defense spending, and painting it as a negative. Perhaps this signals that the Obama team is confident that his advantage on national security is such that Romney won’t be able to demagogue the defense spending issue against him. Whatever the reason, it’s an interesting development, and it will be interesting to see if the Obama camp sticks with this argument.