WASHINGTON -- In the end, after not very much hesitation, Republican Senator Bob Smith of New Hampshire lumbered down the aisle and voted loyally for the GOP version of minicontrols on health maintenance organizations.
There had been doubt about his vote in some Republican circles earlier in the day, but I can't imagine why anyone would have expected him to ditch the party on a big one like health care. After all, as he himself likes to say, ''I'm the most reliable Republican vote in the Senate.''
You could look it up. In a compilation done annually by Congressional Quarterly, Smith edges Idaho's Larry Craig as the Republican most likely to do what most Republicans do on any given vote.
Smith brought this up in the context of his decision to resign from the GOP and try to run for president on a new party or third-party ticket. To borrow former Democrat Ronald Reagan's old line, his party had left him, not the other way around.
And he's right. The party that at least officially went right-to-life 20 years ago with Reagan, is downplaying that commitment today when it is not looking for ways to fudge it or weaken it. The party whose platform has consistently sought the closing down of serious chunks of the federal government or the evisceration of others has no intention in practice anymore of doing either. The party that also has pledged not to permit the ceding of any American sovereignty to an international organization routinely does exactly that. And its previously adamant position against federal controls on gun ownership erodes a little more each week.
Most Americans, myself included, would probably applaud these shifts. And many conservatives are averting their gaze in the rush to climb aboard the cash-heavy bandwagon of President-in-waiting Bush. Meanwhile, many Republican politicians are condemning Smith for being a renegade and vowing that his career is mortally self-wounded, and many in both parties are openly mocking his quixotic quest, complete with its self-comparisons to the Smith that Jimmy Stewart portrayed as going to Washington 60 years ago.
Much of it is crude, even cruel, and quite possibly politically way off base.
As Smith and other movement conservatives like to say, with good reason, the Republicans have done just fine when they stuck firmly to conservative principles (the Reagan victories of 1980 and '84 and the congressional earthquake a decade later). And they have not done so well when they have tried to soften those principles (the presidential defeats of 1976, '92, and '96.
To understand why Smith has a serious point (evidenced by the nodding heads of more prominent conservatives even as they said they would stick with their party for now), it helps to understand where this guy comes from.
He comes from the grass roots, where people with strong beliefs, including the belief that beliefs matter, are most likely to be found in politics today. Smith was brought up in New Jersey, but he was formed in the insular world of town life in New Hampshire after his Navy service, teaching school, coaching sports, and selling a little real estate.
His formative political experience was doing grunt work for Barry Goldwater in 1964, but he came to life backing Ronald Reagan. The second time around for Reagan in 1980, Smith was so energized that he tried to jump from school board service to Congress from the state's first district.
That, he says, is when he got his first taste of what George W. Bush's truly conservative opponents are calling the Republican establishment. A heavy from Washington came up to see him, trying to persuade him to quit the race and clear the field for a more moderate candidate. He refused, lost the primary, won nomination two years later, and made it here in the Reagan landslide of '84.
He hasn't changed; but his party clearly has.
Smith's decision to resign his membership will cost him. He probably loses any hope of moving up to chair the Senate's Environment and Public Works Committee after Rhode Island's John Chaffee retires; he loses party support if he decides to seek reelection three years hence after a near-defeat in '96.
But that's not how he sees it. This is an activist who has decided that his party no longer means much of what it says, that its establishment has become downright hostile to people like him.
And that's why the real question following Smith's decision is not how many other party figures follow him into disillusionment. It's how many grass-roots activists decide there is no more cause worthy of their anonymous toil.
Bob Smith could be the tip of a real iceberg of turmoil on the right. As usual, he spoke for a lot more conservatives than was evident last week from the snickering his principled decision elicited.
Thomas Oliphant is a Globe columnist.
