Washington —- Government secrecy is emerging as a hot political issue among the presidential contenders, gaining traction alongside such dilemmas as the Iraq war, the economy and policy failures such as immigration.

Barack Obama has seized the transparency issue, portraying Hillary Clinton as "one of the most secretive politicians in America today" for failing to release her tax returns and hasten the release of her White House records. She has also come under criticism for her husband's decision not to disclose donors to his presidential library.

Obama also criticized Clinton for failing to disclose requests for special state projects known as earmarks.

Clinton's campaign responded by comparing Obama with Ken Starr, a prosecutor who aggressively pursued her husband for lying about his affair with a White House intern.

Obama should stop "stonewalling" on questions about his connection to an indicted political fund-raiser from Chicago, Clinton aides said, not mentioning that there is no established link between Obama and that person's legal trouble.

Republican Sen. John McCain is not immune to attacks on the topic. He has come under fire for failing to release his tax returns and medical records.

The contest over who is the most transparent presidential hopeful comes as a new survey finds that 75 percent of Americans view the federal government as "secretive."

Nearly nine out of 10 say it is important to know presidential and congressional candidates' positions on open government when choosing a candidate, according to a survey conducted by Scripps Howard News Service and Ohio University for Sunshine Week, a national initiative to focus attention on the growth of government secrecy.

The survey shows a significant increase over the past three years in the percentage of Americans who believe the federal government is very or somewhat secretive, from 62 percent of those surveyed in 2006 to 74 percent in 2008.

"Open government is not an issue that stands alone," said Deborah Gersh Hernandez, coordinator of Sunshine Week, noting that government secrecy touches on the war, the economy and immigration.

"It is knowing what your government is doing and your right to know what is going on," Hernandez said. Clearly, the public wants less secrecy, she said.

No lasting impact?

Although secrecy has become an issue for the presidential candidates, political analysts question whether it will have a lasting impact.

Geoffrey D. Garin, president of a leading Democratic political research and polling firm in Washington, said Obama figures the best defense is a good offense, so he is hitting Clinton with secrecy charges. "This allows some chance of changing to a different subject in a way that gets at an underlying concern that people have about Hillary Clinton —- namely that she is not a fully transparent personality," Garin said.

It is not clear if the individual criticism about the tax returns or the contributors to the library resonates with the public, Garin said. "But the idea that Hillary Clinton is not fully open in her dealings with the public goes to a hold-over impression that people have of her that she really is concealing things about her basic motivations," he said.

Both campaigns are walking a "very fine line," said Garin, who is not affiliated with either Democratic campaign.

"Democrats don't want this to become a food fight and they don't want either candidate to conduct themselves in a way that the Democrats could lose the general election," Garin said.

Whit Ayres, president of a leading Republican research firm based in Virginia, said secrecy is more of an issue for Clinton than Obama or McCain because of her "record of reluctance" to release critical documents.

"There's more of a monkey on her back because of the Clintons' penchant for secrecy," Ayres said. Clinton would be a "juicy target" for McCain on this subject if she prevails against Obama, he said.

Clinton is trying to portray her eight years in the White House as first lady as "Camelot years," a period of economic prosperity and good times, said Charles S. Bullock III, a political science professor at the University of Georgia.

'Most open in memory'

But the mention of secrecy in connection with Clinton's name also dredges up memories of Clinton's former law firm records disappearing and then reappearing; the mystery surrounding the suicide of Vince Foster; the questionable fund-raising practices of the 1996 presidential election; the last-minute pardons and the secrecy surrounding her husband's affair with Monica Lewinsky, Bullock said.

"Hillary is trying to portray her experience as a positive thing —- vote for me because I was there —- but calling her secretive brings up the Clinton presidency in a negative way," Bullock said.

Steven Aftergood, director of the Project on Government Secrecy at the Federation of American Scientists, said the attacks on Hillary Clinton for failing to release her records from the IRS and the National Archives are all "minor blemishes."

"The Bill Clinton administration was the most open in living memory, with the strongest declassification program in our lifetime," said Aftergood, a leading authority on government secrecy issues. He says the Clinton administration "set the standard on public accountability."

Aides for Obama and Clinton responded to requests for positions on open government topics. McCain's staff did not respond.

Technology could help

Obama has outlined a transparency plan that would use technology to help the public learn more about how the federal government works.

He said he would air Webcasts of federal agency meetings; put government data online so the public could easily track federal grants, earmarks and lobbyist contracts; and "turn the page on the growing empire of classified information."

Clinton has her own plan to "replace secrecy and mystery with transparency." Among Clinton's proposals: end no-bid government contracts and post all contracts online, publish budgets of every government agency and put more services online. She also wants to protect government whistle-blowers.

And while Clinton has been criticized for failing to disclose donors to her husband's presidential library, she co-sponsored legislation in 2001 that would have required the sitting president to disclose donations or commitments to his or her library foundation totaling $5,000 or more per year. The bill did not pass.

Clinton said she has urged the release of records as soon as possible from the National Archives and Records Administration. "It's a cumbersome process set up by law," Clinton said.

McCain has made lobbying and ethics reform a cornerstone of his campaign, saying "a democratic government operates best in the disinfecting light of the public eye."

McCain has supported the release of Congressional Research Service reports. These reports, paid for with tax dollars, provide in-depth research about government programs. He has also pressed for a federal law to protect the confidential sources of reporters in most cases.