RENEE MONTAGNE, host: Ten years ago today, President George W. Bush signed the U.S.A. Patriot Act, which Congress has passed overwhelmingly after the September 11th attacks. The Patriot Act was designed to give the FBI more power to collect information in cases that involve national security.

But in the past decade, civil liberties groups have raised concerns about whether the Patriot Act goes too far by scooping up too much data and violating people's rights to privacy. NPR's Carrie Johnson has this report.

CARRIE JOHNSON: Nicholas Merrill is an unusual guy. The techie from New York may be one of the few people to fight a request for information from the FBI that came in the form of a tool called a national security letter.

Ten years ago, the Patriot Act made it easier for authorities to demand records from Internet service providers like Merrill's company. But Merrill is the only person who's gone to court to get a green light to talk about it and he's doing so.

NICHOLAS MERRILL: I find it kind of upsetting that there is still so much secrecy surrounding these powers and their actual use, even to this day.

JOHNSON: But even Merrill's court victory has its limits, as I found out when I asked him about the visit he got from an FBI agent back in the winter of 2004.

Well, what kind of information did the FBI want from you?

MERRILL: Unfortunately, I am not at liberty to talk about that because that's one of the things that's still covered under the gag order that I'm under.

JOHNSON: And that secrecy, according to lawyers at the American Civil Liberties Union, is just one of the problems with the Patriot Act. They're bothered by another part of the law, the so-called sneak-and-peek provision. It lets FBI agents search a person's home or business with a judge's blessing but without telling the person they're doing it.

Michelle Richardson works for the ACLU in Washington.

MICHELLE RICHARDSON: We're now finding from public reports that less than one percent of these sneak and peek searches are happening for terrorism investigations. They're instead being used primarily in drug cases, in immigration cases and some fraud.

JOHNSON: What's more, Richardson says the Justice Department doesn't usually point to specific terrorism cases it built, thanks to the Patriot Act, raising questions whether the powerful law really works.

PAT ROWAN: I think a number of provisions have been very useful.

JOHNSON: Pat Rowan led the Justice Department's National Security Unit during the Bush years.

ROWAN: But it's not so much that they can be isolated and pointed to and said, oh well, this particular provision caused the government to discover a plot it otherwise wouldn't have discovered.

JOHNSON: Instead, he says, the Patriot Act made investigations more efficient, by giving investigators in national security cases many of the same tools they had in criminal cases. And by encouraging intelligence operatives and law enforcement agents to share information.

Viet Dinh, the former Justice Department lawyer who wrote the Patriot Act, says despite all the criticism from civil liberties groups, most people couldn't tell you what's in the law.

VIET DINH: There's no question that the USA Patriot Act has become a brand, if you will; a symbol of all of the counter-terrorism activities after 9/11.

JOHNSON: Dinh says the law simply gave the FBI more flexibility to do its job. And he points out that Congress has reauthorized provisions in the law with only small changes several times in the past 10 years.

Richardson, at the ACLU, says she hasn't given up on efforts to get lawmakers to scrap some parts of the Patriot Act. But she's got her eye on even bigger surveillance efforts in the works now.

RICHARDSON: The White House's cyber security proposal right now makes the Patriot Act look quaint. And really, the collection that it would allow would really outpace anything that's probably being done under the Patriot Act right now.

JOHNSON: Nick Merrill, who wasn't able to talk to his family for years about the FBI request or his lawsuit, wonders how many other people have gone through a similar experience.

MERRILL: It's time to have an open discussion about the direction that our country's going in, in terms of all this secrecy and justifying everything with national security.

JOHNSON: That's a conversation that Merrill hopes to jump start today on the Patriot Act's 10th anniversary.

Carrie Johnson, NPR News, Washington.

MONTAGNE: You're listening to MORNING EDITION from NPR News. Transcript provided by NPR, Copyright National Public Radio.