If you're an air traveler who feels the urge to pull your hair out every time you enter a security line at the airport, you may have considered taking Amtrak or even the bus instead. If so, you may want to scratch that idea. The Transportation Security Administration, you see, is showing up in train terminals. Perhaps you'd rather drive?

TSA has not shown itself to be exceptionally useful for thwarting terrorism. It has never caught a terrorist in its airport checkpoints or anywhere else, as far as anyone knows. But the bureaucratic urge to expand cannot be easily suppressed. Lacking evidence of its value in airline terminals, TSA is branching out to other places where it can be equally ineffective.

The agency "has vastly expanded its reach to sporting events, music festivals, rodeos, highway weigh stations and train terminals," reports The New York Times. Its Visible Intermodal Prevention and Response (VIPR) program, created in 2005, now gets $100 million a year "and is growing rapidly, increasing to several hundred people and 37 teams last year, up from 10 teams in 2008," the Times says.

In 2012, it conducted some 8,800 unannounced operations outside of airports, or 24 per day. No, it's not requiring concertgoers and train passengers to take off their shoes and empty their pockets, but give it time. And never mind that local and state law enforcement agencies used to take responsibility for these venues if they were needed.

Maybe the change of scenery will keep some workers out of trouble. The federal Government Accountability Office says that cases of employee misconduct jumped by 26 percent from 2010 through 2012—everything from sleeping on the job to letting people bypass screening. Last year, an agent at the Newark Liberty International Airport was convicted of stealing $800,000 worth of laptops, cameras and other goods.

Humans being humans, any organization staffed with them will have its share of crooks. But you'd think an agency that has "security" in its name would be especially vigilant in preventing and detecting internal wrongdoing. GAO, however, said TSA doesn't keep track of how all the misconduct cases turn out and has no process to ensure they're handled correctly.

The more pertinent problem, however, is that once established, the agency can't be eliminated. On the contrary, it has a strong tendency to grow. In 2003, Congress limited it to a maximum of 45,000 employees, but—I know this will surprise you—that restriction was later lifted. It now has 58,000.

TSA is the tip of the iceberg. Republicans talk about radically downsizing the federal government, and Rick Perry even proposed to abolish three entire departments. But history tells us that Republican presidents don't close departments; they create them. (Ditto for Democrats.)

Ronald Reagan never followed through on his pledge to kill the Education Department. Instead, he signed a bill establishing the Department of Veterans Affairs.

In the aftermath of 9/11, George W. Bush insisted we needed a new bureaucracy to protect the nation from attack—which we used to assume was the job of the Defense Department. So the Department of Homeland Security came into being, with jurisdiction over everything from guarding our borders to combating counterfeiting.

It was justified as a way to consolidate and coordinate the functions of numerous government bodies with overlapping or complementary tasks. You would expect such consolidation to save money by minimizing duplication.

You would expect that, I mean, if you were born yesterday. If you have been around long enough to be familiar with the ways of Washington, you would expect nothing of the kind. DHS started out with some 170,000 employees and now has more than 200,000. Its budget ballooned by 40 percent, adjusted for inflation, between 2003 and 2012.

Thanks in part to helpful guidance from Congress, the department has funded programs that address no plausible threat. Cato Institute policy analyst David Rittgers noted that it gave $100,000 to a lightly populated Ohio county for a hazardous materials trailer and truck, which the county later sold, deeming it a waste of money. It provided tiny Bennington, N.H., with $6,500 for chemical weapons suits.

It's all a bit much, but in the age of terror, there is no such thing as excessive security. So TSA and DHS will go on finding ways to justify their existence. Threats come and go, but threat responses last forever.