The concerns appear unlikely to force President Barack Obama to push out his Treasury secretary, for whom he voiced renewed support today. But the worries could undermine the Obama administration's efforts to keep Congress on board for a more comprehensive approach to propping up the financial system.
Today, two members of Congress -- Rep. Connie Mack, R-Fla., and Rep. Darrell Issa, R-Calif. -- became the first to call on Obama's Treasury secretary to resign.
"Secretary Geithner either didn't know about the bonuses, and was grossly negligent, or he did know and failed to bring this to the president's attention," Issa, the top Republican on the House Government Reform Committee, said in a statement. "Either way, the end result has been a significant waste of taxpayer dollars and he should take immediate responsibility and resign."
House Minority Leader John Boehner, R-Ohio, stopped just short of joining their calls, telling a radio interviewer that Geithner is "on thin ice." He said the administration needs to provide more details of "what the administration knew and when they knew it."
Several Democrats, while continuing to stand behind Geithner publicly, are serving notice that their patience has limits.
Asked if he supports Geithner, Rep. Michael Capuano, D-Mass., said: "At the moment, yeah. I mean, I have questions like anybody else, but let's be serious. He's still new on the job, he hasn't been able to get anybody else appointed or actually confirmed by the Senate. So, I think it's a little too early to pass that judgment."
Rep. Paul Hodes, D-N.H., who serves with Capuano on the House Financial Service Committee, offered similarly lukewarm support: "I think Secretary Geithner is doing generally a good job, and I'm hoping that he's learning quickly how difficult the job he faces is."
They join a growing number of Democrats who are voicing concerns. Sen. Ron Wyden, D-Ore., is complaining that Obama's economic team is sending mixed messages.
"The president goes out and says this is not acceptable, and then some backroom deal gets cut to let these things get paid out anyway," Wyden told the AP. "They need to put this to bed once and for all."
The Treasury Department declined to comment today on congressional skepticism, citing the president's comment.
Though Geithner declined to appear at a House subcommittee hearing on AIG today, he was a presence in the hearing room -- and not in a positive way.
"I was remarkably disappointed that Treasury Secretary Tim Geithner declined to testify at today's hearing, considering the primary role he played in the governmental intervention into AIG," said Rep. Tom Price, R-Ga., arguing that the country needs "an exit strategy" from bailouts.
Geithner will appear at another House Financial Services Committee hearing next Tuesday, where he's expected to get a grilling from lawmakers on AIG and other matters.
President Obama today issued a strong defense of Geithner, saying he has "complete confidence" in his leadership.