WASHINGTON — In Florida, Sen. Marco Rubio has been attacked as a "traitor." In Arizona, tea party members protested against Sen. John McCain. In Utah, Occupy demonstrators donned black hoods to stand against "radical and uncalled for constraints on our constitutional rights."
The uprising is directed at provisions of the 2012 National Defense Authorization Act, approved by the Senate last week, that would require the military to arrest terrorist suspects in the United States and detain them indefinitely without trial.
The intensity of the debate — from the left and right, primarily about how the law could affect U.S. citizens — underscores how the country is still struggling with profound changes brought by the 9/11 attacks a decade ago.
And it raises fundamental questions about the freedoms that are at the core of the nation, chiefly a right to due process, and whether they apply to the evolving battle lines.
"The last thing a terrorist should hear when they are captured is, 'You have the right to remain silent,' " said Sen. Lindsey Graham, R-S.C., a leading proponent.
Advocates say the changes affirm tools the government already has. Critics say the provisions are too broad, allowing the president to define who is an enemy combatant.
The law would cover those who aid al-Qaida, the Taliban, or associated forces that are engaged in hostilities against the United States, including anyone who has "committed a belligerent act or has directly supported such hostilities in aid of such enemy forces."
President Barack Obama has threatened a veto, arguing the measures would complicate civilian intelligence gathering. FBI director Robert Mueller and Defense Secretary Leon Panetta have objected as well. The bill includes a waiver to keep people in the civilian system, but administration officials say that too is cumbersome and would devour critical time in an investigation.
Despite White House objections, the Senate approved the defense bill by a 93-7 vote Dec. 1.
The approval has triggered fears across the Internet, from concern about innocent Americans being snared to more extreme views of a military state.
"Sen. Rubio, you might want to sit down with your older relatives who fled Cuba and ask them why they left," Erica Cirillo wrote on Facebook, one of several comments. "Could it be that they saw friends and family being detained indefinitely without trials? That innocent people were being grabbed in the street and labeled 'enemies of the state' for no reason? Shame on you, senator."
The blowback was so intense that Rubio, a freshman Republican, wrote a two-page letter explaining his support for the legislation and countering assertions that the military would supplant typical law enforcement activities. "This bill does NOT overturn the Posse Comitatus Act; the military will not be patrolling the streets," Rubio wrote.
The Senate also voted to say the bill does not affect "existing law" but killed amendments that would have stripped out the detainee provisions.
After the 9/11 attacks, Congress said the government could use "all necessary and appropriate force" against terrorists, and that has been used to justify the detainees at Guantanamo Bay. Less clear is the handling of U.S. citizens.
The legislation states that "the requirement to detain a person in military custody under this section does not extend to citizens of the United States."
But opponents say that still leaves the option open. And a related provision saying the government can hold suspects without trial does not include a specific exception for citizens.
Sen. Carl Levin, the Michigan Democrat who co-wrote the language with McCain, has pointed to a 2004 Supreme Court ruling that said the government could hold an American who was caught fighting with the Taliban in Afghanistan. "There is no bar to this nation's holding one of its own citizens as an enemy combatant," Levin said, quoting Justice Sandra Day O'Connor.
But others say the situation is different: The suspect, Yaser Esam Hamdi, was overseas in a time of war. O'Connor also referred to a citizen "captured in a foreign combat zone."
Sen. Jeff Merkley, D-Ore., pointed to the case of an Oregon lawyer who was jailed in connection with 2004 bombings in Madrid but later released after the FBI conceded fingerprint evidence was wrong. If the man, who was awarded $2 million in damages, had been detained by the military he might have been held without the ability to clear himself, Merkley said.
"We have to look at the issue and say, 'America, is this what we want to do?' " said Sen. Dianne Feinstein, D-Calif., who offered one of the amendments to remove the detainee language.
(Rubio voted against her amendment; Florida Democratic Sen. Bill Nelson was in favor of it, though, like Rubio, voted for the overall defense bill.)
The legislation is now in the conference process with the House, which would have to accept the detainee language. Tea party members and liberal Democrats, who have been warned against the provisions by the American Civil Liberties Union, may feel the squeeze.
Rep. Allen West, a tea party Republican from South Florida, said he supports the changes and ticked off the names of recent terrorist suspects caught in the United States. On Wednesday he was named to the panel that will negotiate with the Senate. "There's more of this coming," West said, "and we've got to get serious about understanding that we're being infiltrated right here in our own country."
Alex Leary can be reached at email@example.com. Follow him on Twitter @learyspt.