I thought Romney missed one easy opportunity to paint the President as an amateur in foreign policy on the situation of Russia and sanctions against Iran.
It is widely known that, but for Russian and China, the sanctions against Iran could have been stronger. OK, I still commend the President for getting it done, but I think any fair critic realizes that they could have been more effective.
Now, lets look at Russia. Not long into his term, Obama pulled out of the missile defense shield in Poland, to the great surprise of many, not the least of which was Poland. This made Russia very happy of course. What I would have liked to seen Obama do at the time, was use that as a carrot to get Russia to sign on to stronger sanctions against Iran, which he did not do. Essentially, we gave that missile defense program away for nothing, when a smarter political operator would have gotten something out of that.
That is one example, I am sure there are others, and I am sure that there are opportunities that the President could have taken as well.