Former New York City Police Commissioner Bernard Kerik said Wednesday U.S. security officials are doing a better job of protecting Americans than ever before, but a Paris-style attack will take place in the United States.
"That's going to happen here. Eventually they're going to get through. We're going to miss one of these things, and they're going to get through and pull off a stunt like this," he told CNBC's "Squawk Box."
"Intelligence is going to be the success or failure of us preventing these attacks."
The extremist group ISIS claimed responsibility for the deadly terror attacks in Paris.
Kerik, who was police commissioner during the Sept. 11 attacks on New York, compared preventing a terror plot in the United States to fighting drug cartels in the 1970s and '80s.
"We do this, they do this. We do that, they do this. It's a constant, moving thing that we have to be prepared for, and we're doing the same thing in terrorism," he said.
He said policing in the United States changed two weeks ago with the Nov. 13 Paris attacks because everyday cops who respond to an active shooter now must be prepared to encounter attackers outfitted with bomb vests and be on guard for secondary explosions.
"An everyday cop has to think like one of these troops going into a circumstance in Iraq or Syria," he said.
Still, Kerik said, the Macy's Thanksgiving Day Parade, which is expected to attract 3 million people, should go on, despite a worldwide State Department alert warning Americans to be vigilant in public places.
"I can't see cowering to this enemy, and that's what they want. They don't want that parade. They don't want the freedoms that we live by."
Kerik briefly served as interior minister of the Iraqi Coalition Provisional Authority following the Iraq War and was nominated by President George W. Bush to lead the Department of Homeland Security, but Kerik withdrew his nomination. He was sentenced to four years in prison in 2010 after pleading guilty to felony charges that included tax fraud and making false statements to the federal government while being vetted for senior positions.