Americans these days have to be on guard against seemingly endless attempts to invade their personal privacy — identity theft, burglars harvesting home addresses from car registrations while the owners are at the movies, even scam artists giving away their possessions online. Now we must add to that list our own government failing to protect what should be one of the most secure documents on the planet: a United States passport.

Americans these days have to be on guard against seemingly endless attempts to invade their personal privacy — identity theft, burglars harvesting home addresses from car registrations while the owners are at the movies, even scam artists giving away their possessions online. Now we must add to that list our own government failing to protect what should be one of the most secure documents on the planet: a United States passport.

First came the news that contract employees had snooped in Sen. Barack Obama's passport file at the State Department. Then it turned out that the files of Sens. Hillary Clinton and John McCain had also been compromised.

Now it appears the files of some high-profile Americans were breached at least 20 times since January 2007.

These reports raise a number of concerns.

The State Department has been using outside contractors to help with the flood of passport applications since the government began requiring air travelers entering the country from Canada, Mexico, the Bahamas and Bermuda to show passports. That's concern number one.

State Department officials insist the contract employees are screened just as thoroughly as in-house workers. But that clearly didn't prevent unauthorized snooping.

Obama's files were breached three times and McCain's once; two contractors were fired and third disciplined for those incidents. Clinton's files were breached once when a department employee used her name during a training exercise. That employee was reprimanded.

It's not clear that any really sensitive information was compromised. Passport files normally contain only basic application data — name, age, Social Security number, birthplace. But the potential is more serious.

The department also maintains more personal data: marriages overseas, court orders, arrest warrants, medical and financial information. This is information that should be carefully safeguarded.

Then there is the issue of an apparent double standard for protecting information. The latest revelations came to light because the incidents involved possible snooping in the "flagged" files of certain high-profile Americans, whose names are on a special list of about 500 because they are politicians, movie stars or athletes. Opening those files triggers an automatic notification that the file has been viewed.

Certainly such people have more reason than the ordinary citizen to fear snooping by the curious and the ethically challenged. But why should their personal information be more valuable — more "personal" — than anyone else's? This is supposed to be a nation of citizens equal in the eyes of the law and of the government.

Looking at the file of a citizen not on the list generates no automatic notification. So there is no way to know how often the files of "ordinary" Americans may have been improperly viewed.

The breaches of privacy are under review. The undersecretary of state conducting the review has suggested expanding the list of people with flagged files and requiring a supervisor's approval before any flagged file is viewed.

Those are reasonable steps, but they do nothing to protect the millions of Americans not considered high-profile enough to warrant special security measures.