" If you have something that you don't want anyone to know," Google CEO Eric Schmidt said in 2009, "maybe you shouldn't be doing it in the first place."

This line was creepy enough coming from one of President Obama's confidants and fundraisers. It takes on added weight now that the Washington Post and the Guardian have reported that the National Security Agency's Prism program, in the days before Obama was sworn in, tapped into Google's servers, gaining access to every message sent or received over Gmail.

Google spokesmen, like spokesmen from all the tech companies, deny participating in any such program. So Americans are left to wonder: Was this corporate-government collusion? Was this federal hacking or infiltration of corporate servers?

These are murky questions, so let's return for the time being to Schmidt's point, and the question it raises: If you're upset about the government reading your emails, or knowing whom you call -- when, from where, and for how long -- then what are you hiding?

In other words, why should law-abiding citizens mind federal surveillance?

The answer begins with this distressing reality: None of us scrupulously obeys the law. Technically speaking, we're all criminals.

Federal and state criminal statutes have multiplied like rabbits over the decades, and so now everyone breaks the law, probably every day.

Copy a song to your laptop from a friend's Beyonce CD? You just violated the Digital Millennium Copyright Act. Did you buy some clothes in Delaware because they were tax free? You're probably evading taxes. Did you give your 20-year-old nephew a glass of wine at dinner? Illegal in many states.

Citizens that the federal government wants to indict, the federal government can indict if it monitors them closely enough. That's why it's so disturbing to learn that the federal government doesn't need to obtain a warrant on us in order to get our emails and phone records.

But these surveillance powers are used only for hunting terrorists, Obama says. Even if you take him at his word, because so far there is no evidence to the contrary, think about the capabilities you give to government when it can snoop on your phone records and emails.

Maybe Obama hunts only terrorists with it. But our next president could expand it to follow violent felons -- without having to get specific warrants. Why not drug dealers and sex offenders? Tax evaders come next.

One threat to privacy is Congress expanding the use of these Big Brother tools. Another threat is an administration using it illegally. This happens. President Bush used surveillance powers inappropriately. New York Gov. Eliot Spitzer targeted political opponents with state surveillance.

So what's next? A president targeting hard-core environmentalists or pro-life activists on the suspicion they'll carry out terrorist attacks? This may not sound likely, but recall scare stories about "ecoterrorists," and how Obama's Department of Homeland Security has warned that Tea Partiers are serious threats.

You don't need a new Nixon for this to become reality. You just need a president convinced that his political opponents are not only incorrect, but positively dangerous.

Also, privacy has real value, even when you're doing nothing wrong. You're not "hiding something" when you shut the door to use the bathroom or take a shower. A husband and wife might be very proud to show off their kids, but still expect privacy regarding the process of making such children. It's the same with communications.

It's reasonable to not want anyone reading your email fights with your sister, or your groveling apology to your wife. It's perfectly legitimate to say your credit card purchases are none of the government's business.

The Fourth Amendment recognizes this -- it protects Americans from unreasonable searches. This isn't just a protection from cops rifling through your file cabinets. The Supreme Court has repeatedly held that this protection isn't merely from disruption, but also from a search invading your privacy.

President Obama, on some level, clearly understands all of these arguments -- that's why he's tried so hard to keep his administration's secrets. Why has Obama so aggressively prosecuted leakers? Does he know he's doing something bad? Or does he value secrecy only for those with good intentions?

Why did Obama keep Prism and the phone-call-data-harvesting project secret?

If Presidents Obama and Bush have something they don't want people to know, as Obama's pal Schmidt puts it, maybe they shouldn't be doing it in the first place.

Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at tcarney@washingtonexaminer.com. His column appears Monday and Thursday, and his stories and blog posts appear on washingtonexaminer.com.