Critics say that bringing the men onto U.S. soil will create hazards for Americans, a concern that Obama has dismissed.
"I'm a prosecutor myself," said Holder. "The reality is based on all of my experience...that I am quite confident that the outcome in these cases will be successful."
But Holder's reassurance likely won't silence his critics.
House Minority Leader John Boehner, R-Ohio, called the decision irresponsible, saying in a statement, "The possibility that Khalid Sheik Mohammed and his co-conspirators could be found 'not guilty' due to some legal technicality just blocks from Ground Zero should give every American pause."
Michael Mukasey, former attorney general for the Bush administration, says that the men who plotted 9/11 weren't deterred by the prospect of being tried in federal courts.
"At least those moving this process forward," Mukasey wrote in a recent article in the Washington Post, "should consider whether the main purpose here is to protect the citizens of this country or to showcase the country's criminal justice system, which has been done before and which failed to impress Khalid Sheik Mohammed."
Sens. Sen. Lindsey Graham, R-S.C., John McCain, R-Ariz., Joe Lieberman, the Connecticut independent, and Jim Webb, D-Va., failed last week to push through an amendment that would have prohibited the prosecution of any individual suspected of involvement with the 9/11 attacks from being tried in Article III, or federal, courts.
On his first day of office, Obama signed an executive order to close the detention camp at some point. Although the original deadline for closure was January 2010, administration officials have said that it could take longer.
In May, the president said that some detainees would go to federal court, and that others would be tried in military commissions revamped by congressional legislation. Today, Holder announced that five cases, including that of Abd al Rahim al Nashiri, accused of plotting the 2000 attack on the USS Cole which killed 17 U.S. sailors, would be held in revamped military commissions.
In theory, military commissions have less stringent procedural standards for evidence that may have been obtained in the heat of war. Military commissions have also been preferred as a more secure method to protect sources and methods of intelligence gathering.
But officials have not yet said what the administration plans to do with the nearly 210 other men being held.
The administration has found three countries willing to take 25 detainees whom it no longer considers a threat, and hopes to transfer many more out of the country.
A looming question, however, is what to do with detainees who will not be charged but are too dangerous to release.
Congress recently passed legislation allowing the administration to bring onto U.S. soil those men that it plans to charge but the legislation only dealt with those who were being criminally prosecuted.