It is without a doubt that this election is about jobs and the economy, as it was in 2008. However, the complete and total lack of foreign policy bona fides from the GOP's VP pick was enough to throw voters towards a relatively inexperienced Barack Obama.
In the last debate, we saw President Obama come out of his comfortable zone of politeness, and play some smash-mouth, helmet-to-helmet football with Mitt Romney. And, since Romney is an entitled wuss who can't take a punch, it was successful. Obama had his most successful fundraising day, and likely staunched the bleeding in the polls from the disastrous first debate.
Obama blitzed Romney, early and often. In the first debate, Obama gave Romney all the time he needed to sit back in the pocket and pick his targets. Once you rough Romney up a little bit, his passes are less accurate. He starts feeling pressured. He throws an interception when he looks like he's driving for a touchdown ("Please proceed, Governor.") Romney couldn't handle smash-mouth.
Obama, for all the hangups I have about some of his policy decisions as a commander-in-chief, is most decidedly a hawk from the Kennedy tradition of foreign policy. Romney has 0 experience in foreign policy, and while Barack Obama started with the same, he has a track record of success.
Obama must contrast his success as a commander-in-chief with Romney's weaknesses. In the same breath, Obama must hit him negatively and promote himself positively. The flip-flopper image, and perhaps mentioning "Romnesia" could be helpful.
Obama must criticize Romney in a way that makes himself look like a hawk while making Romney look like, well, someone who's positions have been unclear, noncommittal, or wrong.
Examples include:
"Governor Romney insists that he is different from George W. Bush, but when it comes to foreign policy, most of his advisers are former Bush advisers. He has the same people who gave bad advice to George W. Bush giving him the same bad advise. I don't want to go back to a Bush foreign policy, the American people don't want to go back to a Bush foreign policy, but that is exactly what Mitt Romney would do." (He should have some of the advisers memorized, especially the 16 of 24 figure.)
"Governor Romney criticized me in the 08 campaign for unequivocally stating that borders would not stop my administrations pursuit of Osama Bin Laden. He called it irresponsible. I think that he has definitively been proven wrong."
"Governor Romney wanted to use ground forces and start another ground war in Libya. That wasn't necessary to oust Qaddafi; I was able to see that the Libyan people freed themselves without wasting American blood and treasure unnecessarily. If Governor Romney was President, we'd be fighting a 3rd ground war in Libya, instead of wrapping up our last one in Afghanistan."
"Governor Romney doesn't support a timeline in Afghanistan. I believe this is irresponsible because it conveys weakness to the Karzai government about the seriousness of our intention to leave. Our timeline makes sure that the Afghans know that we are leaving, and its their responsibility to secure their own country. Governor Romney would prolong our stay in Afghanistan, already our longest ground war in history, even though we have achieved our primary objectives of crippling Al Qaida central and taking out Osama Bin Laden."
"Governor Romney called our withdrawal from Iraq a 'tragedy.' I for one am glad our brave men and women are home safe, and believe they did so honorably."
All these would serve to keep Romney on the defensive, and as soon as he begins to deny it, a simple "that's not true, Governor," would force him to eat up his own time defending himself, rather than attacking.
Keep his defense on the field, and it will tire and give up points.