WASHINGTON >> A diabolical range of recent attacks claimed by the Islamic State — a Russian airliner blown up in Egypt, a double suicide bombing in Beirut and Friday’s ghastly assaults on Paris — has rekindled a debate over the proper limits of government surveillance in an age of unrestrained terrorist mayhem.

On Monday, in unusually raw language, John Brennan, the CIA director, denounced what he called "hand-wringing" over intrusive government spying and said leaks about intelligence programs have made it harder to identify the "murderous sociopaths" of the Islamic State.

Brennan appeared to be speaking mainly of the disclosures since 2013 of the National Security Agency’s mass surveillance of phone and Internet communications by Edward J. Snowden, which prompted sharp criticism, lawsuits and new restrictions on electronic spying in the United States and in Europe.

In the wake of the 129 deaths in Paris, Brennan and some other officials sounded eager to reopen a clamorous argument over surveillance in which critics of the spy agencies had seemed to hold an advantage in recent years.

Civil libertarians warned that at just such moments of fear, the government would reach for new, and unjustified, authorities.

"As far as I know, there’s no evidence the French lacked some kind of surveillance authority that would have made a difference," Jameel Jaffer, deputy legal director of the American Civil Liberties Union, said. "When we’ve invested new powers in the government in response to events like the Paris attacks, they have often been abused."

The debate over the proper limits on government dates to the origins of the United States, with periodic overreaching in the name of security being curtailed in the interest of liberty. This era of al-Qaida and the Islamic State in some ways resembles battles U.S. and European authorities fought in the late 1800s with anarchists who carried out a wave of assassinations and bombings, provoking a huge increase in police powers, according to Audrey Kurth Cronin, a historian of terrorism at George Mason University.

Since then, there were the excesses of McCarthyism exploiting fears of Communist infiltration in the 1950s, the exposure of domestic spying and CIA assassination plots in the 1970s, and the battles over torture, secret detention and drone strikes since Sept. 11, 2001.

Europe has its own complicated history. In Germany, the history of Nazi and Communist repression made the public and some politicians especially receptive to Snowden’s assertions that the NSA was out of control. In France and Britain, the reaction to the leaks was far more muted.

On Monday, Prime Minister David Cameron of Britain suggested that he might fast-track aggressive surveillance proposals dubbed by critics the Snoopers’ Charter, while President Francois Hollande of France called for a package of tough measures, stepping up surveillance and permitting raids without warrants.

In the United States today, surveillance is the core issue for the security agencies combating the Islamic State, and for the watchdog groups that monitor those agencies. In addition to the basic question of how much government snooping should be allowed, there is the particular concern of Muslims that they are being unfairly targeted.

Rep. Peter T. King, R-N.Y., who serves on the House Intelligence and Homeland Security committees, said on Fox News Sunday that "we have to put political correctness aside."

"We have to have surveillance in the Muslim communities," he said. "That’s where the threat is coming from."

Farhana Khera, executive director of Muslim Advocates, a legal and civil rights group, said it made no sense to target all Muslims. "I think all Americans want to be kept safe from violence of any kind," she said. "But we know that blanket surveillance of people based on religion and race doesn’t work."

Many security experts believe that compared with Europe, the United States is at far less risk of a large-scale jihadi attack, especially those directed from Syria. Flights into the United States and controls at the Mexican and Canadian borders make it difficult for assailants to reach U.S. soil. And the Muslim community in the United States is proportionally smaller and is seen as far better integrated and more prosperous than in France and some other European countries.

Whether because of such factors, or because of government surveillance and other measures, the toll of jihadi terrorism in the United States since the Sept. 11 attacks has been very small, less than three dozen killed. After Paris, "It’s possible that now, everything has changed — a phrase you heard after 9/11," said John Mueller, a political scientist at Ohio State and co-author of "Chasing Ghosts: The Policing of Terrorism," said. "But I doubt it."

For some intelligence officials, however, the toll in Paris is proof that they need all the powers they have, and perhaps more. A major consequence of Snowden’s disclosures was the Obama administration’s decision to drop the mass collection of the phone call logs of millions of Americans’ metadata. The NSA was directed to use more selective measures in part because there was no evidence that the phone log program, under Section 215 of the Patriot Act, had actually thwarted any terrorist plots.

Michael V. Hayden, former director of both the NSA and CIA, said that collecting phone logs did no harm and might, in the rare event of a major plot, have done good. It was designed, he said, to foil a Paris-style plot — "unknown people inside the homeland who are communicating with terrorists abroad."

"In the wake of Paris, a big stack of metadata doesn’t seem to be the scariest thing in the room," Hayden said. Of Brennan’s complaints about the damage of leaks and worries about invasion of privacy, he said of current and former intelligence officials, "We all feel that way."

Timothy H. Edgar, a scholar at Brown University who has worked for intelligence agencies and for the ACLU, said the debate over surveillance had become too polarized. The rush to extreme measures after Sept. 11 was counterproductive, he said. But in recent years, some critics’ sweeping condemnation of all surveillance was an overreaction, too, he said.

"There are lessons to be learned," Edgar said, speaking of Paris. "But we don’t know what they are yet."

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