Republican presidential candidate Mitt Romney (L) and President Barack Obama talk to each other during the second presidential debate at Hofstra University on October 16, 2012. - 

President Obama and Mitt Romney meet in Florida tonight for the final presidential debate of this election. The theme is foreign policy, but economic issues underlie most of the topics.

Expect another tough exchange on how the Obama administration handled security leading up to the deadly attacks on Americans in Libya. Iran, Afghanistan, Iraq and terrorism are sure to come up, but apart from that, look for the candidates to boil most issues down to economics.

China may again stand accused of currency manipulation, but Council on Foreign Relations senior fellow Sebastian Mallaby says that line of attack may be behind the times.

“Partly in response to pressure from the United States, the Chinese have changed their policy,” he argues. “They’ve allowed their currency to get stronger and sure enough, their trade surplus has come down a lot.”

The challenge for both candidates is to connect foreign policy challenges like defense, trade and the euro crisis, to pocketbook issues voters care about. There will be tough rhetoric, but fireworks on stage won’t necessarily move traders.

“The markets are smart enough to realize that what people say in a debate and what they actually do when they get into office may not be the same thing,” Mallaby says.

Follow Mark Garrison at @GarrisonMark