White House officials said Thursday that the acquittal of Ahmed Ghailani on all but one of more than 280 criminal charges in the 1998 bombings of U.S. embassies in East Africa would not undermine their effort to try former Guantanamo detainees in civilian court, even as the mixed verdict reignited debate over that policy.

White House press secretary Robert Gibbs said Ghailani - the first former detainee to be tried in federal court - will receive a lengthy prison sentence for his conviction on one count of conspiracy.

"In the case of Mr. Ghailani, there was a guilty verdict, a minimum sentence of 20 years that incapacitated somebody that has committed a terrorist act and because of that incapacitation is not going to threaten American lives," Gibbs told reporters.

Gibbs deflected questions about where future trials will be held but said President Obama "remains committed to closing Guantanamo Bay," a process that would require trying detainees in civilian courts or in the military commissions established during the Bush administration.

Republican lawmakers, however, said the verdict should force the administration to abandon the civilian trials. "I am disgusted at the total miscarriage of justice today in Manhattan's federal civilian court," said Rep. Peter T. King (N.Y.), the ranking Republican on the Homeland Security Committee. "This tragic verdict demonstrates the absolute insanity of the Obama administration's decision to try al-Qaeda terrorists in civilian courts."

After deliberating for five days, a jury found Ghailani, 36, guilty of conspiracy to damage or destroy U.S. property but acquitted him of multiple murder and attempted-murder charges for his role in the bombings.

The Obama administration had hoped that a conviction on most, if not all, of the charges would help clear the way for federal prosecutions of other Guantanamo detainees - including Khalid Sheik Mohammed and four alleged co-conspirators accused of organizing the Sept. 11, 2001, attacks.

President Obama's strategy, however, has run into fierce, cross-party opposition in Congress and New York, where the administration once hoped to try Mohammed, in part because of concerns that it would be harder to win convictions in civilian court. Senior administration officials said in recent interviews that Mohammed and other accused 9/11 conspirators will probably remain in military detention without trial for the foreseeable future.

The failure to convict Ghailani, a native of Tanzania, on the most serious terrorism charges bolstered the arguments of those who say the military prison at Guantanamo Bay, Cuba, should be kept open, both to host military commissions for some prisoners and to hold others indefinitely and without trial under the laws of war.

Even so, administration officials said that the Ghailani case should be seen as an example of what can go right in federal court: There were no safety threats resulting from trying him on U.S. soil, as some critics have said there would be if Mohammed were tried in New York. "Not once was there a security concern" from the transfer or the trial of Ghailani, Gibbs said.

Ghailani could be sentenced to up to life in prison. He is the fifth person convicted for his role in the bombings in Nairobi, Kenya, and Dar es Saalam, Tanzania, which killed 224 people, including 12 Americans.

At the Justice Department on Thursday, spokesman Matt Miller said the case will ultimately yield a long prison sentence. "One of the strengths of the criminal justice system is its ability to handle difficult cases," Miller said. "This was a difficult case in that there were questions about Ghailani's treatment during the previous administration" - such as the use of enhanced interrogation techniques - "that led to a key witness being excluded."