As noted on Friday, there's been a significant shift in the public's perception of which candidate is the most competent on foreign affairs. While Obama retains a lead, it has shrunk considerably over the past few weeks - a result, no doubt, of the Benghazi attack and the president's poor performance in the first debate.
So public opinion on which candidate is better equipped to deal with foreign policy challenges is in play tonight in a way it hasn't been since the campaign began (not that foreign policy is expected to matter all that much this cycle).
As for the specific issues set to be discussed tonight, the Chicago Council has usefully rounded up its polling to get a sense of where Americans stand on issues such as China, Iran, terrorism and America's role in the world. The Council on Foreign Relations has also done a deep dive on the issues and where the candidate's stand here.
The challenge for Romney tonight, I think, is to go a bit beyond the trite sound bites ("peace through strength" and "apology tour") and offer us some real detail on how he would conduct business differently. For President Obama, it's trickier - he will try to paint Mitt Romney as a neocon warmonger while gently eliding the fact that his own policies and rhetoric have put the U.S. on a course to war with Iran.
What we won't see tonight, however, is a debate between two fundamentally different foreign policy worldviews. For all the partisan huffing that must attend an affair like this, both candidates promote rather orthodox foreign policies. They both accept that it is America's obligation to "lead" the world, with such leadership expressed largely in terms of military adventures. Neither men will make the case for any kind of significant reappraisal of U.S. interests in light of the Arab Spring or the rise of powers such as China and Brazil. Both will champion bogus goals like "energy independence." Neither will suggest that the U.S. seek to minimize its global responsibilities in light of its crumbling finances.
In short, the "debate" will likely be a rather narrow one, fought within a consensus about what constitutes U.S. vital interests and America's global role. But who knows - maybe there are some surprises in store.
Remember, you can join us here for a debate live tweet with a host of foreign policy experts representing a nice cross section of views. The page will go live shortly before the debate begins tonight at 9:00 pm ET. Readers can participate as well - check out the instructions here.