Editor's note: Ruben Navarrette Jr. is a member of the San Diego Union-Tribune editorial board, a nationally syndicated columnist and a regular contributor to CNN.com.
San Diego, California (CNN) -- Michael Bloomberg is out a quarter. That's how much New York's mayor, who has an estimated net worth north of $15 billion, wagered that he knew exactly what type of person would try to set off a car bomb in Times Square.
I'm sorry for Bloomberg's financial setback. But he can take comfort from the fact that he taught Americans a valuable and timely lesson about the dangers and limits of profiling.
The lesson: Profiling -- especially of the racial and ethnic variety -- isn't just wrong. It's also imperfect. It can lead police to focus on the wrong people while the right ones get away.
In October 2002, Washington authorities -- in pursuit of a serial killer in the Beltway sniper attacks -- spent days looking for a white male because that's what the profile says serial killers look like. Ultimately, two suspects were arrested, charged and convicted. Both were African-American.
In the case of the New York bombing plot, before any arrests were made, Bloomberg told "CBS Evening News" anchor Katie Couric that the suspect was likely a domestic, anti-government terrorist acting alone.
"If I had to guess 25 cents," he said, "this would be exactly that -- homegrown, or maybe a mentally deranged person, or somebody with a political agenda that doesn't like the health care bill or something. It could be anything."
A person who doesn't like the health care bill, eh? Why not just say the words "Tea Party" and get it over with?
Now that an arrest has been made, let's see how Bloomberg did in his attempt to play FBI profiler.
The bombing suspect, who reportedly admitted his role in the plot and was charged by federal authorities, is a 30-year-old Pakistani-American named Faisal Shahzad. He is not homegrown; Shahzad was born in Pakistan and became a naturalized U.S. citizen.
Apparently, he didn't act alone but rather as part of a conspiracy; authorities in Pakistan have made at least a dozen arrests in connection with the attempted bombing.
There is no evidence that Shahzad is mentally deranged; while he obviously could have benefited from reading "Car Bombs for Dummies," he also allegedly participated in a premeditated international conspiracy. And, finally, there's no evidence that Shahzad is a member of the Tea Party movement or even drinks tea.
He doesn't seem to have been motivated by an opposition to Obama-care; an official familiar with the investigation said Shahzad thought Islam was under attack.
So, it seems, Bloomberg's profile didn't hold up very well. But he wasn't alone. The day before Shahzad was arrested, I heard a radio talk host in Los Angeles -- a conservative but also a critic of the Tea Parties -- speculate that the attempted bomber was a "right-wing militia type." That's how profiling works. People use it to fit whatever political agenda they're pushing at the moment.
Of course, it's one thing when politicians acting as pundits jump to conclusions about a terror suspect. There's no evidence that Bloomberg's theory about the profile of the bomber drove the investigation down what would have been a dead-end road. It's a bit more serious when law enforcement agencies are encouraged to jump to conclusions about who could be an illegal immigrant. Then you're playing with fire.
Let's say, you live in the state of Arizona. And let's say that, after at least two decades of hiring illegal immigrants or at least turning a blind eye to friends and neighbors who do, you and other 'zonies are suddenly afraid -- not of Mexican drug cartels but of changing demographics, taco trucks, Spanish billboards, having to "press 1" for English, quinceañeras, and other signs of the cultural apocalypse.
Why you might be willing to buy a pig and poke and support a ghastly, half-baked law that -- as originally written and signed by Gov. Jan Brewer -- didn't just allow for racial profiling of people (read: Latinos) who look like illegal immigrants (although even Brewer admitted to reporters that she doesn't have the faintest idea what an illegal immigrant looks like) but all but required it by threatening law enforcement agencies that refused to do this kind of dirty work.
This is how broken the law is. It had to be "fixed" before the governor's signature had even dried. One week after Brewer signed the law, apparently without reading it carefully, she took a "do-over" and signed an amendment intended to address concerns about the potential for racial and ethnic profiling.
Shows how much I know. I would have thought a halfway-competent governor would have made sure those concerns were addressed before signing the bill in the first place.
Be that as it may, one of the changes is that, under the revision, police officers can hunt for illegal immigrants only in the course of enforcing some other law or ordinance. Before, it was open season. Another change is that now the state attorney general or a county attorney cannot investigate complaints that are, in any way, based on a person's race, color or national origin. Before, the law allowed for race, color and national origin to be considered as one of several factors and only prohibited law enforcement from focusing "solely" on those characteristics.
Those changes do not satisfy one of the law's most spoken critics from the world of law enforcement -- Pima County Sheriff Clarence Dupnik. A law enforcement veteran who has been on the job for more than 50 years, Dupnik has had the courage and good sense to call Senate Bill 1070 what it is -- a "stupid" and "racist" and "unnecessary" law.
Dupnik thinks the law is a license to profile and said he won't enforce it because it's impossible for his deputies or any other law enforcement in the state to make a judgment call about who is or isn't an illegal immigrant without taking race and ethnicity into account.
Take it from the law enforcement professionals. Profiling may make for good politics. But, in the hands of those who lack the proper training, it makes for lousy police work.
I think most Americans understand that. They know that, when police are looking for lawbreakers, casting a wide net isn't the best way to go. The more details you have about a suspect, the better off you are. And they bristle when it's their group being caricatured and targeted. How dare someone make generalizations about us or groups with which we identify? Yet we have no trouble condoning the practice when it's done to someone else.
Maybe what we should be profiling for is hypocrisy. Having situational ethics is the same as having no ethics at all.
The opinions expressed in this commentary are solely those of Ruben Navarrette Jr.