Gallup's daily tracking poll released Sunday showed President Barack Obama's approval at 39 percent -- the lowest level to date. According to the poll, 54 percent of Americans disapprove of the president's performance.
The results come as Obama leaves on a bus tour Monday to Minnesota, Iowa and Illinois in an effort to launch a counteroffensive against a growing anti-incumbent mood.
In his weekly radio address, Obama blamed Republicans for crushing people's hopes and dreams.
"You have a right to be frustrated," Obama told listeners. "I don't think it's too much for you to expect that the people you send to this town start delivering."
"Some in Congress would rather see their opponents lose than see America win," the president said.
Over the weekend, Republican hopeful Rep. Michele Bachmann, R-Minn., told a cheering crowd that the results of Iowa's straw poll "sent a message that Barack Obama will be a one-term president."
Bachmann won the poll with 29 percent of the votes, edging out Rep. Ron Paul, R-Texas, by 1 percent.
Gov. Rick Perry announced his candidacy Sunday for the Republican nomination.
Perry, who is the nation's longest-serving governor, said the Obama administration has "an insatiable desire to spend our children's inheritance," saying the "economic disaster" he's overseeing has been "downgrading our hope for a better future."
"I'll work every day to try to make Washington, D.C., as inconsequential in your lives as I can," Perry vowed.
AP contributed to this report.