The latest terror threat alert issued by the U.S. government is the sixth such heightened alert status since the attacks of September 11, 2001. But with no actual attack yet materializing, experts say many Americans may be suffering from what might be called "alert fatigue."

In New York, contractor Tom Le Grecca says that despite the higher security alert there, life goes on as normal.

"You're on a higher sense of awareness than usual, but life goes on and everybody's working and everybody shows up and just deal with the traffic and the security issues," he said.

John Pike, a longtime defense and security analyst with GlobalSecurity.org says people are becoming immune to the warnings, but he says this latest threat may wake people up because the information is so specific.

"People had stopped paying attention to these color-coded alerts because they didn't know what to do about them and nothing ever happened," he said. "This one is different. It is sufficiently specific that, at least in the affected areas, people are going to be very focused on it."

But news that much of the information on which the alert was based is several years old has sparked a mix of fear, skepticism and even suspicion about political motives in an election year. Larry Johnson, former deputy director of the State Department's Counter-terrorism office and a veteran of the CIA, labels the alert as "an overreaction and unwarranted."

"There are some who become, you know, frightened and very concerned," he said. "And there are others who say the, you know, 'there they go again' syndrome. And it becomes no big deal, and in fact, raises the suspicion that it's being done for political reasons, you know, as part of the campaign."

Speaking in New York Tuesday, Homeland Security Director Tom Ridge strongly denied any political motivation behind the alert.

"The detail, the sophistication, the thoroughness of the information, if you had access to it, you'd say we did the right thing," he said. "Government should let the public know about situations like this. It's not about politics. It's about confidence in government telling you when they get the information."

Subsequent news stories quote unnamed government officials as saying some portion of the intelligence pointing to terrorist targeting in New York, Washington and New Jersey was in fact more recent than earlier reports had suggested.

Former counter-terrorism official Larry Johnson says the government has to be more judicious in issuing terrorist warnings to keep the public from becoming jaded.

"I admit that there are wolves out there in the world. I'm not saying that there is no threat or that the terrorism is non-existent, but I am saying that we have to be very careful about going out and providing people information that then does not pan out," he said.