President Obama's assertion of executive privilege Wednesday to prevent the release of documents tied to the botched Fast and Furious gun-tracking operation is just the latest example of his unmet pledge to "usher in a new era of open government," according to government watchdogs and Republican critics.

Obama entered office three years ago as a self-proclaimed reformer, vowing to kick down the walls of secrecy that he said defined George W. Bush's presidency. But on Wednesday, Obama embraced the very tactic that he once accused Bush of trying to "hide" behind.

Obama asserted executive privilege to prevent congressional Republicans from seeing potentially sensitive discussions among top administration officials, in a development that concerned advocates of open government.

"It's not what we like to see; it does not mesh neatly with the administration's self-portrayal on transparency," said Steven Aftergood, director of the Federation of American Scientists' Project on Government Secrecy. "We think disclosure and responsiveness to congressional investigations makes for better government."

The White House counters that it was trying to protect documents that included internal deliberations over how to respond to Republican lawmakers' subpoenas and not hiding those about the gun-tracking operation itself.

And Obama's top surrogates were quick to point out that the episode marked Obama's first use of executive privilege, while Bush invoked the privilege six times and President Clinton used it 14 times.

But when Bush invoked the privilege in refusing to hand over to Congress documents tied to the firing of nine U.S. attorneys in 2007, then-Sen. Obama told CNN's Larry King, "I think the administration would be best served by coming clean on this. The American people deserve to know what's going on there."

One of the hallmarks of Obama's self-trumpeted transparency is that he opened up White House guest logs for the first time. But critics say meetings with controversial figures are often held away from Pennsylvania Avenue to limit publicity.

And public information requests -- like those sent to the Bush administration -- often get selective answers or are ignored entirely despite statutes calling for timely and adequate responses, analysts said.

Viewed through the prism of Obama's predecessor, though, watchdog groups do see improvements.

Bush's attorney general, John Ashcroft, ordered administration officials to withhold requested documents if there was "a sound legal basis" for rejecting a request. In comparison, Janet Reno, President Clinton's attorney general, said records should be blocked only if the "disclosure would be harmful."

The feud between the administration and Congress over Fast and Furious extended to the campaign trail, where Obama's supporters said they welcomed a debate with presumptive Republican nominee Mitt Romney. Obama's surrogates highlighted Romney's refusal to release all of his tax returns and his purging of computer drives when he left the Massachusetts governor's mansion in Boston.

And even some watchdogs who have been critical of Obama's transparency record found little to fault in his use of executive privilege -- at least in this isolated case.

"To be fair, it appears the Justice Department has provided a high-level number of documents," said Anne Weismann, chief counsel for the Citizens for Responsibility and Ethics in Washington. "The dispute is pretty narrow. It just represents the gross politicization of the whole congressional process."