FLETCHER, N.C. — Tea party activists, once unquestioned as a benefit to the Republican Party for supplying it with votes and energy, are now criticizing GOP leaders at seemingly every turn.
They're demanding that Congress use upcoming budget votes to deny money for puting President Barack Obama's 2010 health care law into effect, despite warnings the strategy could lead to a government shutdown.
They're upset that Republicans didn't block a Senate-passed immigration bill.
Many are outspoken opponents of any U.S. involvement in Syria's civil war.
A recent Pew Research Center survey found that more than seven in 10 self-identified "tea party Republicans" disapprove of GOP congressional leaders' performance.
Many of the major tea party groups are backing 2014 primary challengers against Republicans the activists deem too moderate, including Senate Minority Leader Mitch McConnell. The Kentucky conservative once declared it his job to make Obama a one-term president.
That leaves some Republicans quietly worried that an intraparty tussle could yield a repeat of 2012. That year, conservative candidates lost winnable Senate races, and GOP presidential nominee Mitt Romney struggled to win over conservatives while still appealing to moderate swing voters.
The health care debate puts the GOP in its tightest spot. Wary Republicans recall the 1995-96 government shutdowns under President Bill Clinton, who persuaded many voters to blame the GOP and House Speaker Newt Gingrich, a Georgia Republican, for that budget impasse.
McConnell, House Speaker John Boehner, R-Ohio, and other GOP congressional leaders endorse the idea to "defund Obamacare." But some also have tried to persuade core supporters that it won't happen because Democrats run the Senate and Obama won't gut his signature domestic achievement.
If Congress doesn't agree on appropriations at all, then many core government functions, including some military operations and the processing of Medicare claims and Social Security applications, would stop.
But that doesn't satisfy the tea party faithful, who say too many Republicans have welcomed their support in elections only to ignore their concerns in office.
Amy Kremer, leader of the California-based Tea Party Express, spent much of the congressional summer break on a national tour intended to pressure Republicans into backing the defunding movement.
"My message to Speaker Boehner and (House Majority Leader) Eric Cantor and Senator McConnell is simple: If you're not willing to fight for this, what are you willing to fight for?" she said at a recent stop in western North Carolina.
Her group has helped elected conservative favorites such as Sens. Rand Paul of Kentucky, Marco Rubio of Florida and Ted Cruz of Texas, who have driven the campaign for cutting off money for Obama's law.