House Republican leaders thought they'd come up with the perfect legislative strategy for dodging a politically risky government shutdown while still taking a symbolic shot at President Obama's increasingly unpopular health care reform law.

They planned to pass a budget bill that would fund the government and Obamacare, but require Senate Democrats to go on the record supporting the unpopular health care reforms, which Republicans could then use against them in the 2014 elections. Before the bill got a vote, however, support among the GOP rank and file collapsed, forcing House Majority Leader Eric Cantor, R-Va., to withdraw it.

That sudden, unexpected defeat for House Republican leaders, the public would soon learn, was largely the work of two Tea Party stars in the Senate, Mike Lee of Utah and Ted Cruz of Texas. The freshman duo — Lee was elected in 2010; Cruz, in 2012 — convinced conservatives in the House to push for a much more definitive defunding of Obamacare, even if it meant derailing a budget bill needed to keep the government open beyond Oct. 1.

"Just a few weeks ago the Washington Establishment said the Republican-led House of Representatives could never pass a funding bill that would keep the government open while defunding Obamacare," Cruz wrote recently on the political website Real Clear Politics. "They were wrong."

The efforts of Cruz and Lee to defund Obamacare brought scathing criticism from Democrats and cringes from fellow Republicans, who disliked the health care law but had no appetite for a politically risky government shutdown once Senate Democrats refused to go along with the defunding.

Most Republicans urged a more measured approach to defunding Obamacare instead of the all-or-nothing route Cruz and Lee were pursuing.

"I think one of the things we are struggling with is establishing what's a realistic expectation for what we can accomplish when we control one out of the three parts of the elected government," Sen. Pat Toomey, R-Pa., said on MSNBC.

But House Republicans, who were eager to stop Obamacare but thought the defunding strategy would backfire politically, were warned that if they supported the leadership's temperate approach they'd face a backlash from the Tea Party and other conservative groups as elections neared, an aide to Lee told the Washington Examiner.

Lee argued to House Republicans that red-state Democrats facing re-election next year would be particularly vulnerable if they had to vote to retain the Obamacare funding.

House Republicans got the message and passed a tougher resolution that would defund Obamacare. Moments after the House passed it, GOP leaders publicly dared some of those red-state Democrats — Sens. Mark Begich of Alaska, Kay Hagan of North Carolina and Mark Pryor of Arkansas — to vote against it.

The kind of influence wielded by Cruz and Lee — unheard of in another era when freshmen kept their mouths shut and deferred to their elders — wasn't bestowed by the Republican establishment. Indeed, their influence comes largely from their opposition to that Establishment.

Both men were underdogs in their races, but still managed to beat candidates backed by the Republican Party.

Cruz won a tough primary battle against Texas Lt. Gov. David Dewhurst, a fellow conservative who not only raised much more money than Cruz but also enjoyed the backing of popular GOP Gov. Rick Perry. Lee scored an improbable victory over three-term Republican incumbent Bob Bennett in Utah.

The duo credits grassroots activism — Cruz called it a "grassroots tsunami" — for their electoral success, and they continue to court those conservative activists from Capitol Hill.

Both lent their names and faces to the website, collecting 1.6 million online signatures from people who want to stop the health care law. In July, Lee circulated a letter pledging to oppose any government budget bill that funds Obamacare and collected signatures from 14 like-minded Senate colleagues.

"Cruz and Lee are being incredibly effective," said Mike Needham, who runs Heritage Action, the advocacy arm of the conservative Heritage Foundation. "They are recognizing political power today doesn't lie in Washington, it lies around the country."