Even as the U.S. confronts two long wars, neither Sen. John McCain nor Sen. Barack Obama believes the country should take the politically perilous step of reviving the military draft.
But the two presidential candidates disagree on a key foundation of any future draft: Mr. Obama supports a requirement for both men and women to register with the Selective Service, while Mr. McCain doesn't think women should have to register.
Also, Mr. Obama would consider officially opening combat positions to women. Mr. McCain would not.
"Women are already serving in combat [in Iraq and Afghanistan] and the current policy should be updated to reflect realities on the ground," said Wendy Morigi, Mr. Obama's national security spokeswoman. "Barack Obama would consult with military commanders to review the constraints that remain."
According to his campaign, Mr. McCain supports the current Department of Defense restrictions on women in combat units, including armor, field artillery and special forces.
In 1980, President Jimmy Carter revived the Selective Service system, which compiles a list of nearly all men in the U.S. between 18 and 25 in case a crisis forces the government to undertake a massive expansion of the military.
Both Congress and the Supreme Court have exempted women from registration because of the combat rules.