Washington -- California Democrat Dianne Feinstein joined Kentucky Republican and Tea Party favorite Rand Paul on Tuesday in a failed attempt to block legislation that would allow the government to imprison American citizens indefinitely without trial if they are suspected of terrorism.

An amendment they backed to strip the provisions from a broad defense bill failed in the Senate 60-38.

"The U.S. government should not have the ability to lock away its citizens for years and perhaps decades without charging them," Feinstein said, comparing the legislation to the internment of Japanese Americans during World War II. "We don't pick up citizens, we don't incarcerate them for 10 or 15 or 20 years until hostilities end - and no one knows when they will end - without giving them due process of law." Detainees would be held in military detention.

Speaking as chair of the Senate Intelligence Committee, Feinstein declared that the nation "is safer than it has ever been before" from terrorist attack and that some 300 civilian terrorism prosecutions since the Sept. 11 attacks prove the system is working.

Feinstein cited the so-called "American Taliban," John Walker Lindh from Marin County, who was sentenced to 20 years in prison, and Jose Padilla, also a U.S. citizen, who was convicted of plotting a radiological or "dirty bomb" attack and sentenced to 17 years in prison.

Paul was one of only two Republicans who voted to strip the so-called detainee provisions, while 17 Democrats voted with the rest of the Republicans to keep them in the broader legislation.

The bill has drawn a veto threat from the Obama administration and raised an outcry on the left and the right, opening a crack in what has been since 9/11 a united Republican front favoring broad war-making and detention powers by the executive branch.

Early Wednesday, the Senate voted 88-12 to limit debate on the legislation and move ahead. A final vote on the bill could come as early as Thursday.

An act of war

In an emotional debate Tuesday, Sens. Carl Levin, the Michigan Democrat who chairs the Armed Services Committee, and the panel's top Republican, John McCain of Arizona, joined by Lindsey Graham, R-S.C., said the new laws are vital to fighting terrorism.

"If you join al Qaeda, you will suffer the consequences," Graham said. "If you're an American citizen and you betray your country, you're not going to be given a lawyer." Graham said terrorism is not a crime but an act of war.

Paul compared the legislation to Egypt's "emergency law" of 1958 allowing indefinite imprisonment of citizens that helped foment Egypt's revolution last spring.

"We could see American citizens being sent to Guantanamo Bay," Paul said, referring to the U.S. prison in Cuba where terrorism suspects are held by the military without trial. "We should not have to sacrifice our liberty to be safe."

Passage expected

The defense bill is expected to pass the full Senate next month. A House version passed earlier this year.

The House bill also continues the authorization of the use of force Congress granted the president to invade Afghanistan and Iraq. Rep. John Garamendi, D-Walnut Grove, waged an unsuccessful fight last spring to strip that authority.

Garamendi said the provision "gives continuing authority for the president to intervene militarily anywhere in the world where he deems there is a terrorist threat."

He said he found the provision tucked into the defense bill as it was being debated by the House Armed Services Committee "at 1 or 2 in the morning. Everybody had fallen asleep, and I'm reading this 700- or 800-page document, and I asked, 'What's this about? Why are we giving perpetual authority to the president? And the answer was, 'Well, he needs it.' "

Violation of rights

The administration has waged an unusual all-out assault on the detainee provisions, arguing that they violate basic American legal protections and would thwart counterterrorism efforts.

Defense Secretary Leon Panetta; FBI Director Robert Mueller, a holdover from the Bush administration; and Director of National Intelligence James Clapper all sent strongly worded letters to Congress denouncing the requirement of military custody for terrorism suspects.

Mueller said the legislation would confuse lines of authority among civilian law enforcement and the military, and hamper investigations and interrogations.

The White House used unusually strong language in its veto statement, saying placing some terrorism suspects in military custody would be "inconsistent with the fundamental American principle that our military does not patrol our streets. We have spent 10 years since Sept. 11, 2001, breaking down the walls between intelligence, military and law enforcement professionals; Congress should not now rebuild those walls."

Christopher Anders, legislative director for the American Civil Liberties Union, said senators have been under pressure to move the bill quickly and that Feinstein was among the first to put on the brakes. He said a combination of libertarian Tea Party Republicans, especially in the House, and Democratic liberals could prevent a veto from being overridden.

E-mail Carolyn Lochhead at clochhead@sfchronicle.com.