Ornery first-term Republican senators and bomb-throwing conservative activist groups are locking horns again with the Republican establishment.

Tea Party firebrands want to defund Obamacare by threatening to shut down the government at the end of the fiscal year. Other Republicans decry this as irresponsible.

Insurgents say the Establishment doesn't really care about conservative goals. The Establishment says the right-wingers confuse a difference in tactics for a lack of principle.

To understand the tension, it helps to explore the notion of the "Shiny Object."

Mike Needham is the CEO of Heritage Action for America, the lobbying arm of the conservative Heritage Foundation. Heritage Action is the spearhead of the Beltway Tea Party. Needham is the sharp tip of that spear. He's also the author of the Shiny Object theory.

Republican lawmakers want to please their conservative constituents, especially in these days of Tea Party primaries. To mollify the base, GOP members come home touting a conservative vote or a victory over the Democrats. Far too often, Needham says, these supposed conservative accomplishments are just "shiny objects" intended to distract conservative voters from the lack of accomplishments by Washington Republicans.

Needham first used this term with me while discussing the gun control battle of last spring. Republican senators went back to their districts trumpeting that they had defeated Harry Reid's assault-weapons ban.

"There was no chance that an assault weapons ban was going to pass," Needham tells me. Defeating the assault-weapons ban was a shiny object that Republicans could hold out to distract conservatives, providing cover for mandating background checks.

Conservative congressional aides, current and past, complain that this shiny-object method has been the standard operating procedure.

New power dynamics disrupt this.

On gun control, the Tea Partiers refused to let the shiny-object strategy work. Freshman Sen. Ted Cruz, R-Texas, raised a stink, accusing GOP senators of being "squishes" on gun rights. Outside groups ran ads in the districts of GOP senators, ignoring the assault-weapons ban and saying the real fight was the background-check provision crafted by Senators Pat Toomey, R-Pa., and Joe Manchin, D-W.Va.

The grassroots responded, and Republican members heard about it during the congressional recess. Toomey-Manchin failed.

Heritage Action, FreedomWorks, Club for Growth, and Americans for Prosperity -- with their broad networks of local conservatives -- all make the shiny-object trick harder. Politicians are no longer voters' only source of inside-the-Beltway intelligence.

So when a Republican congressman says at his town hall he has voted to repeal Obamacare, the member might get pointed questions from some AFP member or local activist who sat in on a Heritage Action weekly conference call. Obamacare-repeal votes are shiny objects, these groups tell the grassroots. They are not really going to change policy.

The insurgents demand actions that could get real results. "Defund it or own it," Sen. Mike Lee, R-Utah, said on the Senate floor Tuesday. "If you fund it, you're for it."

How can a minority party defund Obamacare? By threatening to kill all appropriations for fiscal year 2014. Republican leaders think this unwise, and they bristle at the suggestion that they're fine with Obamacare.

"We've been fighting this thing with everything we've got for four years," one GOP Senate aide told me. "We don't have a difference in goals, we have a difference in strategies ... The party continues to be united in the effort to repeal it, but this is just not the right strategy."

But Needham and allies argue that the Establishment's strategy equals giving up. He has a point. Many Republicans quietly say what my Washington Examiner colleague Byron York writes: The 2012 election was the last chance to kill this beast.

Needham says he's just trying to hold Republicans to their word: "When they tell their constituents, 'I will come to Washington and do everything I can to block Obamacare,' if they don't do everything they can ... They should have to explain themselves."

This appears suicidal to many. Conservative columnist Ramesh Ponnuru writes: "The chance that Democrats would go along ... approaches zero percent. So if Republicans stay firm in this demand, the result will be either a government shutdown or a partial shutdown combined with a debt default." And Republicans will take the blame.

But even if you can't get your opening ask, the insurgents say, you can get something. Hold out until late September, and maybe Democrats will agree to delay the individual mandate -- or delay the exchanges until the government thinks it can determine eligibility for subsidies.

These conservatives believe Republicans have been fooling them with shiny objects. This time, they want actual scalps.

Timothy P. Carney, the Washington Examiner's senior political columnist, can be contacted at tcarney@washingtonexaminer.com. His column appears Sunday and Wednesday on washingtonexaminer.com.