February marked the fifth anniversary of the reemergence of the label “Tea Party” in American politics. It was in February 2009 that Rick Santelli delivered his famous rant on CNBC, and a few days later, a group calling itself the Tea Party Patriots was organized.

Today the conventional wisdom is that the Tea Party movement is exhausted. Polls are cited showing that only one quarter of Americans express approval of the Tea Party. Democrats run ads claiming their opponents are Tea Party radicals.

Many Republicans argue that Tea Party candidates have lost winnable Senate races, cementing the Democratic majority there rather than overturning it.

There is something to these lines of attack, but it misses a larger picture.

I have likened the contemporary Tea Party movement to the peace movement of the late 1960s and early 1970s. Both began as critics of the more like-minded party: Peaceniks excoriated Lyndon Johnson; the Tea Party decried George W. Bush. Both targeted politicians of both parties.

But both groups soon became mono-partisan, working within one major party. The peace groups secured the Democratic presidential nomination for George McGovern in 1972 and, more successfully, generated support for the young liberals who swept to control in the congressional elections of 1974.

The peace movement permanently changed the character of the Democratic Party. For half a century, starting in 1917, Democrats were the party more inclined to support military interventions. In the almost half-century since then, Democrats have been consistently the more dovish party.

The Tea Party movement has had a similar effect on the Republican Party so far. We shall see if it proves as permanent.

Like the peace movement, the Tea Party movement brought hundreds of thousands, perhaps millions, of people into political activity, people with strong convictions, not on peripheral, but on fundamental issues of public policy. They supplied energy and enthusiasm plainly lacking in the Democratic Party in 1969 and the Republican Party in 2009.

Such surges into politics will bring in many wackos, weirdos and wannabes. But they also include many solid citizens and some with finely honed political instincts.

Both movements supported primary challengers against contrary-minded incumbents or favorites of party insiders. Some of those challengers — most notably Sharron Angle in Nevada and Christine O’Donnell in Delaware — then lost winnable general election races.

But the Tea Party movement also supported some politically gifted challengers — some with considerable political experience (Marco Rubio in Florida, Pat Toomey in Pennsylvania), some with none at all (Ron Johnson in Wisconsin) and some with insider connections among conservatives (Mike Lee in Utah, Ted Cruz in Texas).

On policy, the Tea Party movement has had significant impact as well. It contributed to Republican unanimity against Obamacare and against tax-rate increases.

President Obama predicted that his reelection would “break this fever” of Republican opposition to his policies. Republicans would acquiesce in what Obama seems to regard as common-sense expansions of government.

That hasn’t happened. Instead, policy has moved in the other direction. Republicans were willing to accept the sequester, despite spending cuts, and then to have it only tweaked slightly in the Ryan-Murray budget agreement.

Income tax increases have been avoided on all but couples making $450,000 annually. The result is what liberals call “austerity.”

Meanwhile, Obama has been repealing and revising Obamacare, whether the Constitution gives him authority or not. His signature law is disintegrating.

So Republicans, though only controlling the House and squabbling over tactics, have shifted the vector of national policy. They have had even more policy success in many of the majority of states with Republican governors and legislatures.

Tea Party spokesmen are, unsurprisingly, dissatisfied with the results – as peace advocates often were by policies of even Democratic administrations. But in American politics, policy success is never complete and almost always unsatisfactory to principled purists.

Political reporters chronicling the exhaustion of the Tea Party movement focus on the apparent weakness of primary challenges to incumbent Republican senators and congressmen. None currently seems seriously endangered except possibly 36-year Mississippi Sen. Thad Cochran.

The Tea Party movement continues to be frustrated by a politics-driven Internal Revenue Service and the intractability of Obama and Senate Democrats.

But Republicans have a solid chance to win a Senate majority, and Obama approval is stuck in negative territory. Big government liberalism, hailed as the wave of the future in 2009, now seems widely discredited.

The Tea Party obituaries, like Mark Twain’s, are premature.

Michael Barone, senior political analyst at the Washington Examiner, where this article first appeared, is a resident fellow at the American Enterprise Institute, a Fox News Channel contributor and a co-author of The Almanac of American Politics.