During Operation Desert Storm, some 265,000 reserve and National Guard members were mobilized. Bush, who has the authority to call up as many as 1 million reservists, last week ordered the mobilization of some 35,000 to perform "homeland defense" and civil service functions.
"The troops who will be called up understand better than most that freedom has a cost and that we're willing to bear that cost," the president said Monday.
O'Hanlon says the only scenario under which regular citizens might be called on to bear some of that cost is if the United States moves to occupy one or more countries over a period of several years.
"If we had a five-year occupation … and needed to help shepherd in new governments before we could withdraw — just as we did in Germany and Japan after World War II," he says, "then conceivably you would get into the kinds of manpower requirements that would advise in favor of a draft."
"But that's a quite remote possibility," he adds. "A few percent probability at most."
Since 1980, every able-bodied American male has been required by law to register with the Selective Service System within 30 days of his 18th birthday. It is that system which will swing into action in the unlikely event that Congress passes and President Bush signs legislation authorizing a draft.
"They would have to revisit the entire process of how a call-up would work," says Campbell. "Very little thought has been given to how you would re-institute it."
According to current plans, men ages 20 to 25 would be eligible, with 20-year-olds the first to be drafted. A lottery based on birth dates would be used to determine the order in which people are called up.
"You wouldn't want to get to the situation we had in Vietnam where the rich could 'buy' their way out and educate their way out of the draft," says O'Hanlon. "That was a divisive approach that I think we would want to avoid."
During most of the Vietnam War, any college student was eligible for a deferment from the draft. Current Selective Service guidelines, however, would allow a college student to postpone his induction only until the end of the semester.
A system is also in place to draft a "very small percentage" of the nation's doctors and nurses into military service if the need arises. All health-care workers between the ages of 20 and 45 — both men and women — would be obligated to register.
As with a general military service draft, a so-called medical draft would require the approval of Congress and the president.
"The Selective Service System remains in a standby, caretaker status," the agency said in a statement today. "At this time, there has been no indication from the Congress or the administration that a return to the draft will be necessary."