John McCain and Barack Obama on Iraq and Afghanistan

The surge of U.S. troops in Iraq formally ended over the summer, and the Pentagon is watching to see whether violence continues to decline or unresolved tensions spark renewed conflict. On the campaign trail, Barack Obama and John McCain are answering to voters who are concerned about wars on two fronts.

Turning point. A year ago, with U.S. troop deaths continuing unabated, Americans were wondering if Iraq was a winnable war. But after 30,000 more U.S. troops streamed into the country, moving to small neighborhood outposts and boosting force levels to 170,000, security increased. Equally important, powerful Shiite militia leader Moqtada al-Sadr declared a cease-fire and deadly roadside bombs decreased. Finally, Sunni tribes, who were disgusted by Al Qaeda in Iraq's violence against fellow Muslims, turned on the group and allied with U.S. forces.

Where McCain stands. He was an early advocate of the surge strategy, and McCain says Iraq remains pivotal in fighting Islamic terrorists. He has suggested sending more troops to Afghanistan, where violence is on the rise, but he has not been specific about how an uptick in violence in Iraq would affect the availability of soldiers for Afghanistan.

Where Obama stands. Afghanistan, Obama says, should be America's top priority. He says Iraq "never was" the central front in the war on terrorism and has called for withdrawing U.S. combat forces within 16 months of taking office, leaving behind up to 60,000 troops for support missions. The shift would free up more troops for Afghanistan and cut down on Iraq war expenditures—now some $10 billion a month.

Bottom line. Iraq is less violent but remains deeply unsettled. Obama will have trouble pulling out combat forces as quickly as he wants, while McCain will quickly run into the limitations of a strained U.S. military. Because U.S. troops cannot be two places at once, Americans may have to decide where the greatest threat now lies: in Iraq or in Afghanistan.