With several provisions of the Patriot Act expiring this year, President Obama has his first real opportunity to rein in Bush-era erosions of Americans' civil liberties, while still ensuring national security.

So it's good that the White House last week signaled its willingness to narrow the expansive snooping powers granted the federal government in the aftermath of the Sept. 11, 2001, attacks.

In calling for reauthorization of the authority to search financial records, track "lone wolf" terrorists, and conduct roving wiretaps, a Justice Department lawyer told key members of Congress that the administration would consider stronger privacy protections.

The next day, senior Democratic senators led by Sen. Russell Feingold of Wisconsin put forward a reform measure that was quickly endorsed by the American Civil Liberties Union.

Feingold's bill would make important changes to the FBI's use of so-called national security letters, requiring agents to meet standards for suspecting individuals whose financial records are being sought. While the letters still would be issued in secret under gag orders, they would be subject to greater judicial review to make sure the information-gathering was legal.

That's a legitimate response to inspector-general reports that documented that the national security letters had been used for what amounted to widespread fishing expeditions.

Similarly, the Senate bill would reauthorize roving wiretaps, but only with the proviso that federal agents identify an actual target for surveillance. So-called "John Doe" taps would be banned to avoid sweeping up the communications of citizens with no ties to any illegal activity.

Other key revisions in the law would limit black-bag searches to terrorism-related cases and provide greater legal protection for acts of civil disobedience.

Feingold and his cosponsors are on less firm footing with their proposal to repeal retroactive immunity for telecommunications companies that cooperated in the Bush administration's warrantless surveillance program. While telecom firms should be held to account for future privacy violations, it seems counterproductive to reopen the Bush-era surveillance chapter.

Of all the provisions up for renewal, the authority to track "lone wolf" terrorists not known to be tied to any foreign agent seems the most questionable. Since Obama officials just revealed the provision has never been used, it's pretty clear that national security doesn't require this broad authority.

Wherever possible, the cause of liberty will be best served by restricting government's ability to spy on citizens without their knowledge or consent.

With majorities in both the House and Senate, the president should be able to deliver on his stated commitment to safeguard privacy as a core American ideal.