The Obama administration on Wednesday strongly defended its decision to try the alleged plotters of the Sept. 11, 2001, terrorist attacks in a civilian New York court, but faced criticism from Republican senators who called it a 'perversion' of justice that will risk freeing some of the world's most notorious terrorists. President Barack Obama supported such a trial in interviews with several U.S. television networks before leaving Beijing for South Korea. Casting aside any pretense of assumption of innocence and sounding like the nation's prosecutor-in-chief, Obama said those offended by the constitutional protections being given to Khalid Sheikh Mohammed and four alleged co-conspirators ultimately won't find it 'offensive at all when he's convicted and when the death penalty is applied to him.' But back in Washington, some Republican lawmakers sparred with Attorney General Eric H. Holder Jr. over his announcement Friday that he was transferring the case of the five men from the military commissions at Guantanamo Bay, Cuba to a federal courthouse just blocks from ground zero. Sen. Jeff Sessions of Alabama said the transfer to New York is proof the Obama administration is wrongly 'criminalizing' a war on terrorism in which those captured should be tried as enemy combatants in war crimes tribunals. Others said Mohammed will use a trial expected to be followed by millions worldwide as a stage from which to spew violent anti-American rhetoric, and that it could make New York City a prime target for another terrorist strike. The sharp exchanges at a crowded hearing of the Senate Judiciary Committee were a clear indication that opposition to such a trial will only intensify in the months or even years of legal wrangling before it actually comes to fruition. Several family members of those killed during the attacks on New York and sat directly behind Holder and held up photographs of loved ones. A few cheered when Sen. John Kyl, R-Ariz., demanded to know how Holder could back up his prediction that the five men would be convicted. Holder responded by saying that he had told prosecutors that 'failure is not an option.' Sen. Charles Grassley, R-Iowa, told Holder his response was 'ludicrous,' especially when even one lone juror could sabotage the prosecution's case. 'I'm a farmer, not a lawyer,' Grassley said, 'but I just want to make that observation.' Public reaction to the prospect of the trial has been mixed. New York Mayor Michael Bloomberg and Police Commissioner Raymond Kelly both have supported the administration, as have some victims groups. But some of the attendees at the hearing Wednesday brought a foot-high stack of signatures that they said represented more than 100,000 New Yorkers who are demanding that Obama keep the men at Guantanamo. 'I don't feel that they belong on American soil,' said Theresa Regan, whose firefighter husband, Donald, died at the World Trade Center. 'They took my husband's rights away and they don't deserve to have the kind of rights they will get in a U.S. court.' On the House side, Republican lawmakers intensified their efforts Wednesday to block the trials by prohibiting the transfer of the detainees from Guantanamo to the United States. And Obama, in his televised interviews, also acknowledged for the first time that his administration will miss a self-imposed January deadline to close the Guantanamo detention center, though administration officials have acknowledged for weeks that that was likely. Mohammed and his four alleged accomplices have been at Guantanamo since September 2006, when President George W. Bush ordered them moved from CIA secret prisons overseas so they could face military justice. In more than three hours of testimony, Holder said he was convinced that a civilian court will convict Mohammed, two top lieutenants, an al-Qaida 9/11 paymaster and Mohammed's nephew, all of whom are accused of participating in the plot. And he said federal authorities in New York have a proven track record of prosecuting and safeguarding such complicated trials. 'We need not cower in the face of this enemy. Our institutions are strong, our infrastructure is sturdy, our resolve is firm, and our people are ready,' Holder said. Holder also said he was not worried about whether Mohammed, al-Qaida's chief of operations before the attacks, makes public statements similar to those he made at preliminary hearings at Guantanamo, If he does, Holder said, 'I have every confidence that the nation and the world will see him for the coward that he is. I'm not scared of what Khalid Sheikh Mohammed has to say at trial, and no one else needs to be afraid either.' (Optional add end) At the hearing, Holder's arguments were bolstered by virtually every Democratic senator on the Judiciary Committee, which oversees the Justice Department. Sen. Charles Schumer, D-N.Y., was supportive, but said New York will need federal funds to accommodate what many are calling the trial of the century. He said New York officials recently told him it will cost $75 million just for initial logistics. But Holder's biggest defender was Obama himself, who told CNN that federal courts, especially those in New York, have been used to convict 'hundreds of terrorist suspects' who are now imprisoned in the United States. Obama also said that even though it was Holder's decision to make, he will answer for it, especially if something goes wrong. 'I always have to take responsibility,' he said. 'That's my job.' 