WASHINGTON — The conservative economists and public policy experts who trooped in to brief George W. Bush on Social Security not long after he was re-elected governor of Texas in 1998 came with their own ideas about how to overhaul the retirement program.

But they quickly found that Bush, who was well into preparations for his first presidential race and had invited them to Austin for the discussion, already knew where he was headed.

"He never said, 'What should I do about Social Security?' " said one of the participants in the meeting, Martin Anderson, who had been a domestic policy adviser in the Reagan administration. "On the day we talked about Social Security, he said, 'We have to find a way to allow people to invest a percentage of their payroll tax in the capital markets. What do you think?' "

Bush had long been intrigued by the idea of allowing workers to put part of their Social Security taxes into stocks and bonds. One Tuesday in the summer of 1978, in the heat of his unsuccessful race for a House seat from West Texas, Bush went to the Midland Country Club to give a campaign speech to local real estate agents and discussed the issue in terms not much different from those he uses now.

Social Security "will be bust in 10 years unless there are some changes," he said, according to an account published the next day in The Midland Reporter-Telegram. "The ideal solution would be for Social Security to be made sound and people given the chance to invest the money the way they feel."

Two decades later, Bush's desire to change Social Security intersected with the promotion of private accounts by well-financed interest groups and conservative research organizations, which viewed the concept as innovative if ideologically explosive.

What was once a fringe proposal has been propelled to the forefront of the national agenda in one of the biggest gambles of Bush's political career.

Still, Bush appears unbowed — and no less committed to his approach than he was 27 years ago.

"I've touched it," Bush said in New Hampshire last week, referring to Social Security as the third rail of American politics. "I touched it in 2000, when I campaigned here and around the country. I touched it in 2004. And I really touched it at the State of the Union, because I believe we have a problem."