CEDAR RAPIDS, Iowa — The more President Bush stumps for restructuring Social Security, the less popular his own plan seems to become. His poll ratings are dropping, too, but Bush says he is not deterred.

"I'm going to be stubborn. And we're going to keep working this," Bush told a supportive audience yesterday at a community college here.

Barnstorming on behalf of a presidential proposal is a time-honored technique to build grass-roots support. Bush used the strategy successfully in his first term for his tax cuts and a Medicare prescription-drug benefit.

This time, it doesn't seem to be working.

Not quite five months after a re-election victory that he claimed earned him political capital to spend, Bush's approval ratings are languishing in the mid-40 percent range and his Social Security plan for individual investment accounts seems to be winning few friends, either in Congress or among the general public.

Polls show that Bush, who is about halfway through a 60-day cross-country push for his plan, is helping to raise public awareness of what Social Security's financial plight will be once baby boomers start retiring. But the same polls show that support for individual investment accounts is lower now than when he proposed them in his State of the Union address two months ago.

Sen. Charles Grassley, R-Iowa, who is chairman of the Senate panel responsible for Social Security, said in an interview with The Washington Post: "I don't think [Bush] has made much progress on solving the solvency issue or what to do about personal accounts. It concerns me because as time goes on, I was hoping the president would be able to make my job easier. We are not hearing from the grass roots that, by golly, you guys in Congress have to work on this."

But, sharing the platform with Bush yesterday, Grassley glossed over his differences. "We agree on a blueprint. ... Doing nothing is not an option," he said.

He told reporters after Bush had left that even though the plan lacks support now, "the president knows one of the rules of politics is repetition."

As for Bush's declining approval ratings, some of the president's supporters suggest that other factors, such as the Terri Schiavo case, are at play.

"The president's poll numbers are usually a direct reflection of the national news. And the news has been dominated by a heart-wrenching matter in Florida that has caused many families to discuss politics at the dinner table in a whole new way," said Washington-based GOP consultant Scott Reed.

"I wouldn't throw in the towel on Social Security reform at this stage," Reed said. "The president ... has a very aggressive schedule. I think you have to wait and see what happens when Congress returns from its recess." Congress is back next week.

Pollster Andrew Kohut, director of the Pew Research Center, said the more people learn about Bush's plans for personal Social Security investment accounts, "the less they like the idea."

"The president is saying this is a system that has to be fixed. And people do not see private accounts, personal accounts, whatever you want to call them, as doing that," Kohut said.

Kohut also said that Bush's practice of appearing only before friendly, invitation-only audiences and answering prescreened questions could backfire "if it comes across as hype."

Bush has called for allowing workers under age 55 to divert a portion of their Social Security taxes into stock and bond investment accounts — in exchange for a reduction in future guaranteed benefits.

Critics claim the plan would cost trillions in transition costs. They also say it would not ensure the program's long-term solvency, a point Bush now acknowledges.

Said Thomas Mann, an analyst at the Brookings Institution, "It matters what you're trying to sell. ... when you talk about Social Security, that's real, that's close, that's dear, that's something people care about."