Milton Friedman would be celebrating his 100th birthday today, had he not died in 2006. Were the Nobel-winning economist here today, he would likely have a few words for Thomas E. Ricks, who wrote a New York Times Op-Ed earlier this month titled "Let's Draft Our Kids."

Many people don't know this about Friedman, but he was one of the leaders of the movement to end the draft in the 1970s. He likely would have answered Ricks by arguing that its reinstatement is as terrible an idea today as it was then.

People think that conscription lowers the cost of maintaining a military force. This isn't true. At best, conscription masks the true costs; often, it increases the costs.

Suppose the government needed to pay $500 for a week of military service to induce Joe to volunteer. Suppose this is exactly what he could have earned in another line of work, like running a landscaping company. Superficially, it seems like the cost would be lower if the government could conscript Joe and pay him $400 per week. But Friedman pointed out the fallacy of this thinking. Joe's cost is still the $500 he could have earned with his landscaping company. The difference between what the government would have had to pay Joe in order to get him to volunteer and what the government pays him after conscription is an implicit tax on Joe. In this case, it's $100. The $100 may not show up on the government's books, but it's still a $100 loss.

Ricks argued that "[o]ne reason our relatively small military is hugely expensive is that all of today's volunteer soldiers are paid well; they often have spouses and children who require housing and medical care." But conscription won't decrease these costs -- it will simply force conscripts to shoulder them instead.

Ricks quoted Stanley A. McChrystal's claim that "everybody has skin in the game" when there is a draft. On this basis, many on the political Left argue that conscription would reduce support for war. But a recent study by David R. Henderson and Chad W. Seagren largely debunks this notion. They point out that anti-war activism suffers from a serious "free-rider" problem, and that the sharper incentive the draft creates for private individuals and families is to seek deferments. So, on the whole, conscription imposes massive costs without the benefit of reduced enthusiasm for war.

We also have to face another brutal reality: Conscription is a form of slavery. While Ricks suggests that people should be allowed to opt out in exchange for reduced government services (no subsidized home loans, no subsidized college, no Medicare), he is silent on whether people would have the option of opting out of paying for these services. In a 2006 tribute to Friedman, David R. Henderson quoted a passage from Friedman's memoir:

"In the course of his [General Westmoreland's] testimony, he made the statement that he did not want to command an army of mercenaries. I [Milton Friedman] stopped him and said, 'General, would you rather command an army of slaves?' "

At the end of the day, that's what calls for conscription and compulsory national service are: They are calls to provide military service, education, child care, meals for the elderly or any of a number of other services with an army of slaves. I, for one, do not wish to be defended or served by an army of slaves. At least in the United States, conscription has been relegated to the ashcan of discarded bad ideas. That's where it should stay.

Art Carden is assistant professor of economics at Samford University, a research fellow with the Independent Institute and a senior research fellow with the Institute for Faith, Work, and Economics.