Though many in his own party are wary of tampering with a beloved domestic program, the president said he would push ahead.
"The harder the issue, the bigger the challenge, and the more exciting it's going to be when we get the job done," he said.
Mr. Bush began the day in Omaha, Neb., and then traveled to Little Rock and finally Tampa, Fla. He said he was open to any idea for making Social Security solvent.
"Bring 'em on and we'll sit down and have a good discussion about how to get something done," he said.
The president warned against "scare tactics" in the debate. "We're not going to play political gotcha," he said. "Now is not the time to make this issue a highly partisan issue."
But Mr. Bush's itinerary indicated politics at work. His trip was tailored to pressure Democratic senators representing states that went for Mr. Bush in November — some of them up for re-election next year — to back his idea for letting younger workers put up to two-thirds of their Social Security tax contributions in accounts invested in stocks and bonds. In return, those workers would see an unspecified reduction in their traditional Social Security benefit.
"I fully recognize that the personal retirement account is not the only thing needed to solve Social Security permanently," Mr. Bush said. "But it's a part of the solution." The president has not spelled out the size of benefit cuts that would go along with the private accounts.
He continued to stress that the Social Security system would be "flat bust" in 2042, when it will be able to cover about 73 percent of benefits owed. And he repeated his pledge not to change benefits for those already getting checks or those 55 and older.
A heckler in the Nebraska crowd wasn't buying it. "Quit lying ... you liar," he yelled.
"We love free speech in America," Mr. Bush replied and then continued his speech.
Bush went to Little Rock to woo the backing of Sen. Blanche Lincoln, D-Ark., a centrist Democrat who has supported Bush in the past. She said she "will not allow current benefits to be put at risk."
Mr. Bush's last stop Friday, in Tampa, was aimed at Sen. Bill Nelson, D-Fla., another red-state Democrat facing re-election next year, who said he is leaning against private accounts.
"They will cut Social Security benefits," Nelson told The Associated Press in a phone interview. "I will fight against the cuts to Social Security benefits, the massive borrowing and increase in debt that this will create."
In Omaha, Mr. Bush gently twisted the arm of Nebraska Sen. Ben Nelson, a moderate Democrat who also has sided with Republicans before.
"He is a man with whom I can work — a person who's willing to put partisanship aside to focus on what's right for America," Mr. Bush said.
Nelson, however, said he was disappointed that the president did not disclose more details of his reform plan when he outlined it in his State of the Union address. "I'm looking to be supportive, but I can't support something until I see the entire plan," Nelson said.
The other senator from Nebraska, Republican Sen. Chuck Hagel, talking to reporters in an effort to buck up support for Mr. Bush's plan, said lawmakers were wary of reforming the 70-year-old New Deal retirement program.
"It's politically risky for him and maybe others who support him," Hagel said of the president. "But I think the American public is very wise and understands that this is a program that's going to have to be reformed."
Thursday's travels had Mr. Bush in the home states of Sen. Kent Conrad, D-N.D., the top-ranking Democrat on the Senate subcommittee overseeing Social Security, and Sen. Max Baucus, D-Mont., ranking Democrat on the Senate Finance Committee with jurisdiction over the program. Both were skeptical in interviews of the success in Congress for the president's proposal.
CBS News Correspondent Bill Plante says a long-term fix for Social Security will be painful. Some possibilities on the table:
These are the tough issues Mr. Bush has handed off to Congress to work out, and many lawmakers, including some Republicans, are concerned that personal accounts could add to the problem.
"The fact is, to create personal savings accounts that will be derived from the current payroll tax obviously raises some serious concerns," says Sen. Olympia Snowe, R-Maine, "because it could ultimately contribute to the erosion of the current program."