WASHINGTON – George W. Bush favors guarding the names of donors to his presidential library in Dallas, but Congress has revived a bill that would require him to identify some of them.

The proposal, pending in the Senate after the House passed it in January, does not cover contributions Bush received during his presidency. But if it becomes law, Bush's nonprofit library foundation would have to disclose four times a year all donors of $200 or more for a window of time: starting when the law takes effect until at least 2013.

Future foundations would have to make similar quarterly reports until either the National Archives and Records Administration takes over the presidential library or after the former president has been out of the White House for four years – whichever period is longer. The archives would have to post the reports in an online database.

The bill marks the latest effort by lawmakers, watchdog groups and others to obtain donor lists, saying that allows the public to keep tabs on special interests. A previous measure stalled in the Senate, but backers see a hopeful sign in President Barack Obama's pledge for more transparency in government.

"A $2 million contribution to this new glistening building that's going to have your name on it and is going to be a tourist attraction in your home state is going to go a long way to buying access and influence," said Mary Boyle, spokeswoman for Common Cause, a nonpartisan citizen's lobby.

Even when a president is out of office, she said, they still have prominent roles and it's important to know who is financing their libraries.

Obama, for example, offered the job of secretary of state to Hillary Rodham Clinton on the condition that Bill Clinton release the names of contributors to his library in Little Rock, Ark. His donors included foreign governments and corporations with stakes in U.S. foreign policy.

Presidential libraries are not built with taxpayer money. Instead, Bush – like his recent predecessors – set up a foundation to seek contributions.

Federal law does not require those foundations to disclose all funding sources, and Bush has said many don't want to be identified.

"A lot of donors give to organizations, whether it be this library or anything else, and don't want their names out," he told The Dallas Morning News in an interview in January. "They feel comfortable being anonymous in their giving."

But he said he would follow any new disclosure law but for now, "as far as I'm concerned, I want to honor the desires of the donors. You have to ask donors why they don't want their names disclosed, but there's a lot who don't."

Bush also said he doesn't believe contributors want anything in return. "Once you're ex-president, I can't imagine what kind of policies you could influence that would pay somebody off for a gift," he said.

Lobbyists have to report if they give more than $200 to presidential libraries under a bill Bush signed into law in 2007. Those generally make up a fraction of all contributions.

For now, Bush's foundation – trying to raise $300 million for the library, museum and public policy center at Southern Methodist University – has decided not to disclose the names of other donors, said foundation president Mark Langdale.

And the Bush library Web site says fundraisers must "maintain the confidentiality of all donors and contributions to the foundation."

The library of his father, George H.W. Bush, at Texas A&M University displays the names of major contributors in its rotunda – as a sign of thanks and to show broad support for the project, said Roman Popadiuk, the foundation's executive director. A handful of people requested to remain anonymous, he said.

Last year, the donor bill gained broad support in the House but got held up in the Senate, where then-Sen. Ted Stevens, R-Alaska, vowed to block it unless it excluded Bush.

The new bill, which would affect Bush, passed the House by a wide margin, 388-31. Several Texas Republicans voted against it.

"Presidential library donors are not public officials and should not be subjected to public scrutiny for writing a small check," said Rep. Sam Johnson, R-Plano.

Other opponents said they believed it would create unneeded bureaucracy.

In the Senate, the measure is pending in a committee chaired by Sen. Joe Lieberman, a Connecticut independent who supports the bill. The panel has not yet set a date to consider the measure.

Texas Sens. John Cornyn and Kay Bailey Hutchison, both Republicans, have not yet taken a position on it, aides said.