The most important person to watch in the evolving debate on Social Security personal retirement accounts may be not President George W. Bush, but House Ways and Means Chairman Bill Thomas.

Mr. Bush has used the bully pulpit of the White House to elevate the issue in the minds of the voters – a Fox News poll last week found it was mentioned second most often, after Iraq, as an important issue. But getting personal accounts enacted into law is work that can only be done by Congress. And Mr. Thomas, as the chairman of the House committee with jurisdiction over Social Security and as a legislator with a series of impressive accomplishments over the last four years, is the member of Congress best positioned on his committee and best qualified by his knowledge of policy to reach a solution.

In a National Journal forum on January 18 and then on NBC’s “Meet the Press” on January 23, Mr. Thomas made it about as plain as could be that he believes that personal retirement accounts together with an adjustment of the benefit formula – the policy the Bush White House has been talking about – “cannot, given the politics of the Senate and the House,” be passed in this Congress.

House Republicans are skittish about the issue and would like the Senate to act first. But Democrats – even moderates like the Democratic Leadership Council – are digging in their heels against any changes. It looks like Senate Democrats could get 41 of their 45 members to uphold a filibuster. So long as the issue is binary – up or down on the Bush plan – the result seems likely to be thumbs down. Or so Mr. Thomas evidently believes.

His solution is to broaden the issue. “What I’m trying to do is get out of the narrow moving around of the pieces inside the Social Security box,” he said at the National Journal forum. On “Meet the Press,” he laid out his concerns: “The way we fund the Social Security system, I think, needs to be examined. What we fund it for, chronic or long-term care, has not been addressed, and that’s one of seniors’ major needs.” He pointed out that much of the expected huge increases in Medicare and Medicaid spending will be for chronic or long-term care.

Mr. Thomas is looking not only at benefit changes, but at tax changes. Tim Russert asked him if he favored an increase in the current 12.4% Social Security payroll tax. “Why even bother looking at the payroll tax?” Mr. Thomas replied. “Now that it’s 12 percent, we actually are dealing with a job-killer; the higher the payroll tax, the fewer people are hired.” He seemed to be suggesting a value-added tax, instead. In other words, a massive restructuring of the tax system, in addition to a substantial reshaping of Social Security.

Why would an experienced legislator believe that it would be easier to pass such a complicated and far-reaching law than the considerably simpler measure the White House has been suggesting? Because that’s how Mr. Thomas has been operating over the last four years. On the 2001 tax cuts, the 2003 tax cuts, the 2003 Medicare and prescription drug bill, and the 2004 corporate tax cut, Mr. Thomas put together packages of changes that succeeded in passing. The more moving parts, the more adjustments you can make to gain votes.

On all of these, the House passed one version primarily with Republican votes, the Senate passed a version with a bipartisan coalition assembled by Finance Committee Chairman Charles Grassley and ranking Democrat Max Baucus, and the conference committee, dominated by Mr. Thomas, moved around the parts until it came up with a version capable of passing both the Senate and the House.

It looks like Mr. Thomas is thinking of doing the same thing on Social Security – and taxes. The Bush White House is worried that the process will drag out and that the political capital Mr. Bush accumulated in the election will dissipate. That’s one possible outcome. But it’s also clear that Mr. Thomas has thought hard and long about how to get substantial reform through what is a close and bitterly divided Congress.

Mr. Thomas was first elected to the House in 1978, the year a young George W. Bush ran for a House seat and lost. He has shown legislative skills and policy acumen as Ways and Means chairman every bit as impressive as predecessors like Wilbur Mills and Dan Rostenkowski. His goals sound ambitious. But don’t bet too heavily against him. He has done this kind of thing before.