The more Americans hear about the government tracking their phone calls, the less they like it. It was reported this week that 51 percent of the country had a problem with the Bush administration's indiscriminate collection of private phone records.

Public skepticism about the program has grown significantly since another poll just a few days earlier. The previous poll was done soon after President Bush assured Americans that their privacy had been "fiercely protected."

But the administration didn't really dispute the essential elements of USA Today's story: The National Security Agency has been collecting and analyzing private phone records of millions of ordinary citizens.

According to one source, the NSA eventually hopes to know about every phone call.

So after thinking it over, many Americans decided their privacy hadn't been protected fiercely enough. The new poll found 51 percent to 43 percent disapproval of the phone-records program.

Perhaps even more significantly, two-thirds of the respondents worried that the government might be doing other questionable things that we don't yet know about.

That's an understandable concern. Let's consider some reasons:

n As Knight Ridder's Ron Hutcheson recently recalled, the federal government "has a long track record of abusing personal information gathered in the name of national security."

People in both parties have betrayed the public's trust. Almost every recent president, Hutcheson reports, made questionable requests for FBI information on political opponents.

In the aftermath of abuses in the 1960s and 1970s, a Senate committee noted that government officials could easily overstep the limits of their authority in times of crisis:

"In an era where the technological capability of government relentlessly increases, we must be wary about the drift toward 'big brother government.'"

n Contrary to much of their rhetoric, Bush and Vice President Dick Cheney are in fact enthusiasts of a large and even obtrusive federal government — at least while they are in charge. If they are conservatives, they belong in a special subcategory: big-government conservatives.

The president also chafes at legal and constitutional restraints on his authority. He claims the right to ignore parts of certain laws even when he signs them himself. And he has shown little interest in the Constitution's search-warrant requirements and its prohibition against "unreasonable searches."

This month the libertarian Cato Institute, which has been a strong Bush ally on issues like Social Security privatization, released a study blasting his administration for a "ceaseless push for power, unchecked by either the courts or Congress."

Among the examples cited: unwarranted surveillance.

n The president's credibility problems argue against blind acceptance of the reassuring statements he makes on his surveillance programs.

If you are looking to politicians as role models in the Honesty Department, you are risking big disappointment. But Bush has been worse than most, spinning Texas-sized yarns on everything from his own legislative proposals to — hilariously — his supposed indifference to political polls.

He's now paying the price. In a recent CNN poll, Bush came in behind Bill Clinton, a legendary dissembler, on honesty.

Bush last week further undercut his own credibility by insisting that the government was not "mining" the phone data for information.

The NSA program is obviously all about data-mining — unless the agency is actually listening without warrants to domestic phone calls, which would be even worse.

n Previous reassurances by intelligence officials have proven hollow. Just months ago, for example, Gen. Michael Hayden, deputy director of national intelligence, publicly insisted that telephone surveillance was "focused" and not a "drift net" over the country.

That statement by the man Bush has just nominated to run the CIA now appears to be inoperative. Looks like we've got a drift net.

So the public is right to worry about what else Bush and top intelligence officials might be up to. Everyone, obviously, expects them to take reasonable and effective steps against the country's enemies.

But the key word here is "enemies" — not loyal, law-abiding American citizens.

Stephen Winn is deputy editorial page editor of the Kansas City Star.