WASHINGTON -- President Obama will have to personally sign the death warrant for 9/11mastermind Khalid Sheik Mohammed if the military tribunal he's going to face sentences him to the ultimate penalty.
Mohammed would likely have faced the death penalty in a civilian proceeding -- an avenue the Obama administration rejected yesterday after confronting withering pressure from lawmakers and families of Sept. 11 victims.
They did not want the trial held in lower Manhattan, only blocks from the scene of the monstrous crime.
The rules governing special military commissions, updated by a 2009 law, are entirely different.
The lives of the defendants would be in the hands of a jury of military officers in Guantanamo Bay who would follow special rules for evidence and witnesses.
Among the rules buried in a 2010 procedural manual is a provision that gives Obama ultimate authority over the man prosecutors will charge led the conspiracy to plan the deadly attacks.
"A punishment of death may be ordered executed only by the President," according to the manual.
The president would also have the authority to "commute, remit, or suspend the sentence, or any part thereof, as he sees fit."
But such a reprieve would be highly unlikely.
Obama has written that he backs the "ultimate punishment" in cases that are "heinous" and "beyond the pale."
A Senate staffer told The Post, "there are going to be all kinds of charges brought up on these [defendants] so they'll [Mohammed and his four co-conspirators] certainly be eligible for the death penalty."
But Joanne Mariner, who directs the human-rights program at Hunter College, said, "It's likely to be a really unpredictable trial.
"I've seen KSM in court. He basically tries to plead guilty every time he comes into the courtroom," she said.
That, strangely, could cause difficulty for prosecutors, because military-commission rules are ambiguous on whether a guilty plea is sufficient to get a defendant to the penalty phase.
Sens. Lindsey Graham (R-SC) and John McCain (R-Ariz.) have proposed legislation to clarify that defendants like Mohammed could still be executed if they choose to plead guilty and avoid trial.
Meanwhile, the White House and Attorney General Eric Holder backed the decision to try to Mohammed and his four co-conspirators at Guantanamo -- after realizing there was so much opposition to trying them in New York. Read more:
If they are sentenced to death, Obama will lose a voting base.