It's because even ardent cost-cutters see the so-called "sequester" as a ham-handed and unpredictable way to reduce federal spending. While a few tea party activists are claiming all-out victory, others are keeping their distance, calling the across-the-board cuts the least-bad of several unpleasant options.
"I think it's a crazy idea," said Sen. Marco Rubio, R-Fla., a tea party favorite. "The only thing crazier than sequester is to walk away from the cuts that it guarantees."
Rubio's remarks reflect Republicans' nervousness about how the public might react to the domestic and military spending cuts scheduled to begin Friday.
But in many ways, the sequester marks the tea party movement's maturation into a virtually mainstream role in the Republican Party. Cutting the Pentagon's budget once was unthinkable for most Republican lawmakers. But now it is trumped by the drive to keep taxes down while reducing costs wherever possible.
Congressional Democrats and Republicans agreed to the sequester in 2011 only as a consequence so unpalatable that it would goad them into finding a deficit-reduction compromise. The compromise never materialized, however, and now the nation is about to swallow what lawmakers once called a "poison pill" of their own making.
Republicans fear a possible backlash against program cuts and furloughs of government workers and contractors, especially at military bases. They also worry that the cuts will have an economic domino effect, eliminating thousands of private-sector jobs and possibly pushing the nation back into recession.
If that happens, and if voters decide Republicans are chiefly to blame, then the tea party movement could further divide an already roiling GOP.
President Barack Obama and other Democrats say Republican intransigence on tax increases is the sequester's main cause. And public polls indicate Americans are more inclined to fault the GOP if things go badly, although some Republicans believe they can change that.
For now, the approaching cuts are testament to the power of anti-tax sentiment—and, to a less proven degree, anti-spending sentiment—in the Republican Party. The tea party movement is strongly associated with these sentiments. But it certainly can't take all the credit.
Long before the tea party's birth in 2009, anti-tax activists such as Grover Norquist were pushing the Republican Party to take inviolable stands against new taxes, even as the deficit soared and the federal tax burden approached historic lows.
Obama won re-election after calling for new taxes on the wealthy. He achieved some of them in January. But Republican lawmakers now say "no more," contributing to the sequester impasse.
The tea party has lost much of its exotic flavor that was punctuated by noisy rallies with costumed activists in 2009 and 2010. Its influence, however, appears larger now. "It has melted into the GOP base," said John J. Pitney, Jr., a former Republican staffer who teaches political science at Claremont McKenna College in California. "Anti-tax voters make up a large share of the vote in GOP primaries," he said, "so Republican lawmakers support tax increases at their peril."
But Republicans could face another kind of peril, Pitney said, if the sequester lasts for months and begins to erode "visible, popular programs."
Duke University political scientist David Rohde said the tea party has become "the populist conservative faction of the Republican Party." It drew well-deserved credit for fueling the Republicans' big congressional and gubernatorial wins in 2010, he said, even though some tea party-backed Senate nominees lost key races.
The movement's future, Rohde said, depends on whether tea party activism is seen as helping or hurting Republican candidates in 2014 and beyond. Fallout from the sequester could play a big role in those elections.
Sen. Lindsey Graham of South Carolina is typical of Republican lawmakers who grudgingly accept the sequester and worry that tea party ideals can go too far.
"I believe that the cuts in defense are ill-conceived and will do a lot of damage," said Graham, whose state includes several military installations. "Some of these tea party folks don't mind losing their bases; others will."
The tea party drive to reduce federal spending at almost every level is potent in GOP circles. Rep. Jack Kingston of Georgia, eyeing a Senate race that will draw several hard-right Republican rivals, says the sequester appears inevitable, but it will extract an economic and political price.
Referring to military bases in his Savannah-based district, Kingston said, "my people will take it on the chin." But in constituent feedback about the sequester, he said, "the overwhelming number of people are saying, "Let it happen." They want to see that we are serious about cutting spending."
Even some tea party leaders say the movement's take-no-prisoners approach has its costs.
"Our brand is tarnished, but that's what happens when you get beat up," said Sal Russo, a founder of the California-based Tea Party Express. "It's not the brand" that counts, he said, "it's the ideas."
In the long run, Russo said, the benefits of reducing deficit spending will overshadow any short-term hits to the economy this year. If that happens, he said, the tea party's status will rise in the Republican Party and the nation at large.
The movement "is quite alive and well," he said.
But some question the tea party's willingness to embrace domestic and military cuts that don't touch the greatest causes of deficit spending: the popular but costly "entitlement" programs of Medicare, Medicaid and Social Security.
"They're amputating the wrong limb," said Rutgers University political scientist Ross Baker. If the tea party movement is to achieve its goal of undoing the government's borrowing habits, he said, it must prove it can blaze a political path to reductions in entitlement spending.