WASHINGTON -- The Islamic State has claimed responsibility for the attacks in Paris Friday night, which killed 129 people and injured many more, renewing the discussion about how the U.S. should respond to the militant group. But experts say this debate is obscuring a larger point about America's relationship with terrorism: Put frankly, even the best-calibrated response to the Islamic State, also known as ISIS, will never fully expunge the threat.
"We cannot eradicate terrorism any more than we can eradicate armed robbery," said Andrew Bacevich, a military analyst who was one of the more vocal skeptics in the run-up to the Iraq War. "The best we can hope for is to reduce it to tolerable proportions."
"Eliminating or eradicating the threat is impossible," said Richard Haass, the chair of the Council on Foreign Relations. "We could be 99.99% effective and there would still be enough people to cause real harm. The goal should be to reduce -- dramatically -- the scale of the threat and what it can accomplish."
The notion that the United States will -- for the foreseeable future and likely beyond -- be forced to manage the threat of terrorism rather get rid of it, is not particularly comforting. And it's one that several leading critics of the Obama administration's policy have refused to countenance in the aftermath of the Paris attacks.
Sen. Marco Rubio (R-Fla.), for example, has called the conflict with the Islamic State a "clash of civilizations."
"Either they win or we win," he said.
House Speaker Paul Ryan (R-Wis.) has said that containing ISIS cannot be an option -- a position that House Majority Leader Kevin McCarthy (R-Calif.) echoed in a tweet on Tuesday.
But in conversations with The Huffington Post, former intelligence officials and terrorism experts cautioned that "defeat" -- at least in the context of traditional military engagement -- was wishful thinking. And they encouraged political leaders to base policy on the idea that modern terrorism threats can't be stamped out in totality and, rather, must be managed more effectively.
“It’s not useful to think of the Islamic State terrorism threat in binary terms -- like we either eradicate it or we don’t,” said Max Abrahms, who teaches about asymmetric conflicts at Northeastern University. “That’s not the way terrorism threats tend to operate. They tend to ebb and flow in terms of their intensity. Many groups are operational for decades but the intensity of their violence fluctuates quite a bit.”
Former CIA Director Michael Hayden emailed his thoughts on whether the U.S. could ever eradicate the threat of terrorism.
"Of course not," he wrote. "There will always be alienated people prone to violence. But we can make them less capable and their attacks less frequent and less successful. And in this specific case, perhaps we can facilitate (but not lead and certainly not determine) a dialogue within Islam to address some unresolved (internal) issues."
Richard Clarke, a former top counterterrorism official under Presidents Bill Clinton and George W. Bush, said that the United States should be adopting a more robust focus on CVE activities, or countering violent extremism, and noted that no policy would succeed without addressing the problem at its root.
"Get into the target audience and teach them at an early age that this stuff is wrong: social media, training in mosques, training and youth organizations," Clarke said. "Unless you do that, unless you beat them at the recruitment game, then you will constantly and forever be fighting counterterrorism."
Clarke said it was folly to believe that a robust military response alone would be sufficient to dissuade prospective terrorists from joining ISIS. The fact that recruits to the militant group have already accepted the idea of martyrdom, he explained, "makes them a difficult enemy."
"They are taught once they are brainwashed by these people, that dying is good. So telling them that they are going to kill them -- well, they end up killing themselves. You have to get to them and teach them that Islam really doesn’t say that," he explained.
But that doesn't mean the military component plays no role. Haass countered that the approach to ISIS needed to be holistic: "attacking it, preventing it, defending against it, bouncing back from it when it succeeds, as it will at times." He acknowledged that CVEs were an important long-term component of a counterterrorism strategy, but said military force could be used to halt ISIS' momentum, which serves as a "big recruiting tool" for the group.
To Abrahms, the current military effort against ISIS has been crippled by the Obama administration's “dithering” on its broader approach to the Syrian civil war -- mainly the failure to either remove Syrian President Bashar Assad or decide that he is the better of two evils. Abrahms supports the latter point of view.
“The White House never really made a firm decision on this,” said Abrahms. The equivocation has been compounded, he added, by the administration's opposition to a no-fly zone in Syria, which could have strengthened Syrian opposition groups, as well as by its failure to counteract Russia’s military support for the Assad regime.
“This has been a very confused administration,” Abrahms noted.
All of these approaches assume that there will be no clear or defined end to the threat posed by ISIS. That doesn't mean that the United States will become like Israel -- forced to adapt to, and live constantly with, the threat of terrorist attacks. Clarke noted that Israel is far closer to terrorist threats in terms of geographic proximity, and that it has much less land and fewer targets to protect.
What these experts' arguments do mean is that any effective anti-ISIS strategy will depend, in large part, on patience. Whether politicians and the public can stomach that, after 14 years of war in the Middle East with trillions of dollars spent and thousands of American lives lost, was the lingering question.
Asked whether the American populace could handle terrorism as a constant but simmering threat, Brookings Institution scholar Michael O'Hanlon said, "I actually tend to think our psyches are already there."
"Sometimes politicians just haven’t figured out how street-smart Americans actually are," he added.
This story has been updated to include comment from Michael Hayden.