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WASHINGTON -- A key senator in the issue of terrorism trials said Sunday he will do whatever he can to prevent alleged Sept. 11 mastermind Khalid Sheikh Mohammed from seeing the inside of a civilian courtroom.

Sen. Lindsey Graham, R-S.C., said he has the votes to block Justice Department moves to get civilian trials for the alleged Sept. 11 conspirators and a better place for the Sept. 11 leadership is in a military court at the U.S. naval base at Guantanamo Bay, Cuba.

"I think it is a big mistake to criminalize the war, to take someone you've held under the law of war as an enemy combatant for six or seven years, then put them in civilian court. It is a disaster waiting to happen," Graham said on "Fox News Sunday."

Khalid Sheikh Mohammed "was ready to plead guilty before the Obama administration stopped the trial. We should have him in a military commission trial beginning Monday and get this case behind us," he added.

Graham said he thinks civilian courts may be the right venue for some terrorism cases, such as low-level Al Qaeda operatives and the accused Christmas airliner bomber, Umar Farouk Abdulmutallab, calling it an "all-of-the-above approach to terrorism trials."

In that, he won support from Sen. Claire McCaskill, D-Mo., who, like Graham, has been a prosecutor.

"We need to have every kind of trial available. And each case should be dictated by the facts, the evidence and the circumstances," she said.

McCaskill, who appeared with Graham, said she would also agree to military trials for "the very highest level operatives of 9/11."