Washington ? In many ways, the saga of this Republican era in the House of Representatives can be summed up in the story of Bill Thomas, the California congressman who announced this week that he is retiring as chairman of the Ways and Means Committee and not standing for re-election.

Thomas is an able, principled conservative who has pushed through major legislation that has changed the direction of national policy and altered millions of people’s life prospects. He is also someone who has inflicted substantial damage to the legislative process and to personal relationships on Capitol Hill, leaving bruised feelings in his wake.

In both ways – in what he has accomplished and in the chaos he has wrought – he typifies the mixed record of the 11 years since Republicans wrested control of the House from the long-dominant Democrats.

Thomas, one of the few professional political scientists to serve in Congress, roomed as a freshman in 1979 with a fellow academic named Newt Gingrich, and the two men chafed in similar fashion under Democratic rule. The Almanac of American Politics profile recalls Thomas’ vow at the time that if Republicans ever gained control, “We will not be civilized. We will not assume it’s business as usual. We will not go back to playing the lackey.”

No need to worry. Always one of the smartest and hardest-working members, Thomas came into his own as soon as the Republicans took power. First as chairman of the minor House Administration Committee, he rammed through a set of procedural changes that tightened leadership control of the finances and operations of the House.

In 2001, he was named chairman of the mighty Ways and Means Committee, with jurisdiction over taxes, Social Security, Medicare and welfare. Since then, as he noted in his retirement statement on Monday, “we passed over $2 trillion in tax relief for hardworking American families, we provided the president with trade promotion authority so that he could seek freer and fairer trade markets, and we approved a long-overdue voluntary prescription drug benefit in Medicare for the first time in the program’s history.”

All of those measures were and are controversial, but no one can dispute that Thomas’ imprint on the legislation – and, therefore, on American life – has been significant.

But the achievement has come at a price. What was once a committee whose institutional pride was far greater than its partisan divisions has become a bitter political cockpit, where major national policy is set by party-line votes, rather than through patient negotiation and discussion.

As a result, when Thomas has brought a bill to the floor of the House, it often has had to be muscled through by brute political force. The major trade bill of which he boasted passed 215-214. The Medicare drug benefit was approved only after the roll call was extended to almost three hours in a pre-dawn session while arms were twisted to avoid its apparent defeat.

Personally prickly and often impatient, Thomas quarreled bitterly with colleagues of both parties, but especially with some of the senior Democrats on his committee. His irritation with hard-edged partisans such as fellow Californian Pete Stark was understandable. But he effectively cut out the contributions of such reasonable and able legislators as Maryland’s Ben Cardin, who in earlier years had been able to collaborate with Republicans on meaningful bills.

A low point came when Thomas ordered Capitol police to break up a Democratic caucus in the Ways and Means library – an action for which he later apologized to the House.

The irony in this situation is that the Thomas I got to know during the years when his party was in the minority was a man with a genuine interest in developing the institutional strength of Congress. He regularly offered his own ideas on congressional reform – always with an eye on the legitimate interests of Republicans but with concern that went beyond any narrow partisan or parochial advantage.

But like many others in the House GOP leadership, he has been willing to cut corners and run roughshod over others in order to achieve his policy goals. It is no accident that when the Democrats saw an opportunity to thwart him last year, they refused to consider any compromise on Social Security that did not rule out the private accounts Thomas and the president want.

No bridges had been built between the parties, no basis established for bipartisan talks on an issue of genuine national importance.

Now, facing a Republican-imposed term limit on his tenure as chairman, Thomas is quitting at 64, at the height of his vast intellectual and political powers. You have to wonder how much more he could have accomplished without the strong-arm tactics, and how much less damage he might have caused.