"We're not going to re-implement a draft. There is no need for it at all," Rumsfeld said.
Rep. Charles Rangel, D-N.Y., a Korean War veteran and a strong critic of going to war with Iraq, introduced the bill because, he said, "the burden of military service was being borne disproportionately by members of disadvantaged groups."
Minorities compose more than a third of the military, although they make up only about one-quarter of the American populace.
Rangel also believes Congress and the American public would have less of an appetite for war if more of their children would be involved in it.
"If our great country becomes involved in an all-out war, the sacrifice must be shared," Rangel said when he introduced them measure.
"I don't find that a compelling argument to spend all the money you would spend in churning people through and all the disadvantages that would accrue to bringing people into the service who didn't want to serve in the service," Rumsfeld argued at a news briefing Tuesday.
The 2.5 million-strong military is an entirely volunteer force and has been since 1973, when the draft was ended.
"We feel the all-volunteer force is working extremely well; that it's efficient, it's effective, it's given the United States of America, the citizens of this great country, a military that is second to none," said Gen. Richard Myers, chairman of the Joint Chiefs of Staff.
Rumsfeld also argued that the draft -- at least the way it was implemented during the Vietnam War -- is inherently unfair and ended up putting the less advantaged and less connected at greater risk.
Exemptions and deferments were issued for men in college, he pointed out.
"Today, regardless of what the data is, every single person there is there because they stuck their hand up and said, 'I'd like to do that.' So the argument, it seems to me, is not persuasive," he said.