Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of "Manhunt: The Ten-Year Search for bin Laden -- From 9/11 to Abbottabad." Haley Peters is an intern at New America and a graduate of Duke University.

(CNN) It's the week after July Fourth. And, yep, pinch yourself because you are still alive, as are more than 300 million other Americans.

Last week, as Americans geared up for the Fourth of July holiday, government officials made a number of ominous warnings about potential terrorist threats to the United States.

U.S. Rep. Michael McCaul, chairman of the House Homeland Security Committee, said, "As we approach the Fourth of July, we're going to see a lot more of these (lone wolf-ISIS inspired) attacks."

When asked if he thought Americans could feel safe in planning a trip around the holiday, U.S. Homeland Security Secretary Jeh Johnson replied, "They've got to be particularly careful."

Former CIA Deputy Director Michael Morell said on CBS that he "wouldn't be surprised if we're sitting here a week from today talking about an attack over the weekend in the United States."

The warnings reflected a general consensus among counterterrorism officials that this Fourth of July was among the most dangerous periods we have seen since 9/11.

The concerns partly stemmed from the rising number of homegrown jihadist extremists. FBI Director James Comey recently said that ISIS is attempting to recruit "hundreds, maybe thousands" of potential terrorists in the United States.

In the past year, authorities have arrested around 50 individuals , radicalized at home and conspiring to attack American targets or provide support to ISIS.

This, along with ISIS' call for attacks on the West during Ramadan, which ends in mid-July, and the three attacks inspired or perpetrated by ISIS recently in France, Kuwait and Tunisia, prompted the terrorism alert.

The FBI, Department of Homeland Security and National Counterterrorism Center released a joint intelligence bulletin, alerting local authorities to the threats posed by ISIS and homegrown extremists. U.S. officials, however, noted that there was no "specific intelligence" a terrorist attack was being planned for the Fourth.

The Pentagon increased the force protection level to Bravo , "an increased and more predictable terrorist threat" for bases in the United States.

In Britain, an air base used by American airmen canceled its Fourth of July celebrations due to the increased terror threat.

And then: Nothing happened.

This is not especially surprising given the record of such alerts since 9/11 . Some 15 major terror alerts or warnings have been issued since the attacks on New York and Washington, and none of these has ever been followed by a terrorist attack, or even some kind of plot that was broken up.

Some, such as this past weekend's warning, have been issued in anticipation of major events -- the first and 10th anniversaries of 9/11, for instance, and the Sochi Olympics.

A smaller number of warnings has come as a result of upticks in intelligence reporting.

The warnings rarely achieve much, if anything.

In 2005, former Homeland Security Secretary Tom Ridge even acknowledged that terror alerts were often raised on the basis of flimsy evidence and political pressure.

In December 2003, the Department of Homeland Security raised the threat level from yellow to orange (high) based on intelligence from "credible sources" about imminent attacks that "could either rival or exceed what we experienced on September 11." Dozens of flights from France and Britain to the States were canceled. The Federal Aviation Administration implemented flight restrictions, especially in the Washington area.

New York Times reporter James Risen reported in his 2014 book, "Pay Any Price," that this alert was based on the claims of a government contractor who had convinced the CIA that terrorist groups were using Al Jazeera broadcasts to send targeting information and that using a software he had developed, the agency could decode them.

In the post-9/11 world, there are few incentives not to raise the terror alert and issue warnings. In the event of an attack, any indication that intelligence existed that could have thwarted the attack is damning for the departments designed to prevent them.

Since there was virtually no downside for U.S. national security officials to issue terrorism alerts, the American public has been regularly warned that some kind of serious terrorist attack is in the offing.

Crying wolf, however, does have repercussions. There are significant costs to these terror alerts, both economic and social.

This weekend, local governments and businesses spent significant sums putting temporary security upgrades in place. Some Americans made alternative vacation plans. In the past, many flights have been canceled and commerce impeded.

More fundamentally, the issuing of alerts undermines the essential purpose of counterterrorism -- to prevent terrorist attacks, yes, but also to guarantee American citizens' right to live outside the realm of fear that terrorists want to impose on us. Inflated, ineffectual warnings do not serve the purpose of effective counterterrorism; they contradict it.

We seem to have inverted President Franklin D. Roosevelt's famous admonition "The only thing we have to fear is fear itself" so that our motto today is closer to "We will continually live in a state of self-imposed fear."

When this happens, we are doing the job of terrorists for them.