“ If you see something, send something.” That’s the slogan for Ohio Homeland Security officials’ spiffy new “Safer Ohio” smartphone app, whose release coincides with the one-year anniversary of the Boston Marathon bombings.

It’s “Ohio’s multi-function mobile public safety tool,” the department brags; concerned citizens can use it to snap and submit camera phone pics of anything that raises their hackles, thereby “report[ing] suspicious activity directly to the state’s round the clock public safety intelligence analysts.”

The instructional video that goes with the app is, well, instructive. What kinds of potential perils do Buckeye State bureaucrats want flagged for follow-up? The video provides an example: a picture of what looks like a man-purse lying on the carpet next to an office filing cabinet. “You can send just a message,” the robotic voiceover intones, or text a photo; “Either way, analysts will follow up on every tip.” No wonder they're there around the clock.

Remember Operation TIPS? That was the Bush administration’s 2002 “Terrorism Information and Prevention System,” a scheme to assemble a legion of volunteer citizen-informants drawn from the ranks of mail carriers, utility employees and others with special opportunities to observe and report. The resulting public outcry led Congress to bar the program later that year, in the bill creating the Homeland Security Department. But Homeland Security officials at the federal, state and local levels have apparently concluded that TIPS’s basic concept is sound — so long as you deputize everyone.

We've had more than 10 years' experience with “if you see something, say something,” and the results are nothing to write home about. The brainchild of a now-defunct ad agency, the campaign started in New York City, with posters urging straphangers to phone in tips. By 2008, the Metropolitan Transit Authority was running ads boasting that “last year, 1,944 New Yorkers saw something and said something.” Campaign-inspired calls had resulted in 18 arrests over two years, none terrorism-related.

By 2010, DHS wanted a piece of the inaction, securing a license to take the campaign federal, with then-DHS Secretary Janet Napolitano’s stern monotone echoing through the Washington Metro and Walmarts nationwide.

The Kentucky Office of Homeland Security, which launched its own smartphone app in 2011, offers tips on “Recognizing Suspicious Activity”: it can include “trying not to be noticed” or “avoiding eye contact.” It's “not a hard science,” they admit, but take a crack at it.

There's no indication that any of these programs have worked any better than the original campaign in New York. As Ohio State University political scientist John Mueller notes, his “examination of all known terrorism cases since 9/11 that have targeted the United States suggests that the 'If You See Something, Say Something' campaign has never been relevant.”

That doesn't mean it's been costless. The problem is one of “too many dots,'” as the Congressional Research Service puts it; the “challenge” with suspicious-activity reporting is that it can “result in an avalanche of largely irrelevant or duplicative data while diverting the police from more productive law enforcement activities.”

Worse still, the “say (or send) something” crusade has resulted in government databases filled with “suspicious activity reports” describing constitutionally protected activity like protesting “excessive force by law enforcement.”

As Mueller puts it, such programs have had little benefit save perhaps the dubious one of ”bolstering support for homeland-security spending by continually reminding an edgy public that terrorism might still be out there.”

The campaign for citizen vigilance that began in the subways and is now migrating to our iPhones seems to have done little besides generate an atmosphere of perpetual, low-level anxiety and excuses for official harassment. That's the sort of threat we could stand to be more vigilant about.

GENE HEALY, a Washington Examiner columnist, is vice president at the Cato Institute and author of "The Cult of the Presidency."