Win, lose or draw, Mike Castle was always heading into the Delaware Republican primary as a member of an endangered species. Conservative big game hunters like to call them “RINOs.”

The popular acronym for “Republican in Name Only” has emerged as one of the Tea Party movement’s leading epithets of choice, alongside “liberal” and “progressive.” The upshot is that big-government establishment Republicans are no safer from conservative wrath than the Democrats whose legislation they so often support.

At some point, millions of grassroots conservatives across the country decided there was something wrong, almost abusive, about the right’s relationship with the Republican Party.

Maybe it was buyer’s remorse over the Bush years, when a “compassionate conservative” president and an earmarks-addicted GOP Congress began a deficit spending binge. Maybe it was when they found themselves in the voting booth in 2008, having to hold their nose and think of Sarah Palin in order to vote for John McCain.

But conservatives have finally begun demanding that Republican candidates do more than agree to appear on the ballot with an “R” next to their names. They are looking beyond the party label.

In truth, this is a process many years ongoing: Robert Taft against the Eastern establishment; Barry Goldwater against Nelson Rockefeller; Jeff Bell against Clifford Case; Al D’Amato against Jacob Javits. This year, however, a record number of RINOs have been hunted down and taken to the taxidermist for stuffing.

Alaska Sen. Lisa Murkowski fell to an unknown conservative named Joe Miller. Kentucky Secretary of State Trey Grayson was badly beaten in his Senate race by upstart constitutionalist Rand Paul. Former Lt. Gov. Jane Norton lost a similar race to Ken Buck. Sharron Angle toppled Sue Lowden in Nevada. Sen. Bob Bennett didn’t even make it out of the Utah Republican state convention. Florida’s Charlie Crist and perennial Pennsylvania weathervane Arlen Specter have fled Republican Party to try to extend their political careers beyond primaries they had no hope of winning.

What’s happening? Conservatives have gotten tired of electing Republicans only to get bigger government and massive deficit spending. They are tired of giving their votes and campaign contributions to GOP politicians who pursue conservative goals halfheartedly if at all. They are disgusted that liberal gains, from new government programs to crazed federal court decisions, are seldom reversed but conservative policies like the Bush tax cuts come with an expiration date.

Conservatives are now demanding that their candidates do more than vote for John Boehner for speaker and Mitch McConnell for Senate majority leader. And when asked to vote for liberal Republicans, they lack confidence they’ll even get that much.

Conservatives lack this confidence for good reason. They watched Specter leave the GOP and hand the Democrats a filibuster-proof Senate majority. They watched “Jumpin'” Jim Jeffords of Vermont hand the Senate over to the Democrats in 2001. They let Rhode Island Rockefeller Republican Lincoln Chafee cling to the GOP label only to watch him leave the party and endorse Barack Obama.

For many, Dede Scozzafava in New York’s 23rd congressional district was the turning point. She was a liberal Republican, picked by party bosses despite her unreliability on the handful of issues on which conservatives had some chance of prevailing this year. When the polls showed she couldn’t win, she threw her support to the Democratic candidate.

Rather than vote for Scozzafava, Tea Party activists pulled for the Conservative Party candidate, Doug Hoffman. They were not bothered by the party establishment’s threats that this would cause them to lose the election. Better to an elect an honest liberal, they reasoned, than a liberal in Republican’s clothing.

For how is it a victory to elect a liberal with an “R” next to her name rather than a “D?” What does it profit a movement to win an election but lose its soul? Conservatives are saying to the Republican Party: for years you have taken us for granted. Now you can either win with us or lose without us. And if a conservative candidate loses anyway, so be it.

Rank-and-file conservatives no longer trust the Republican establishment. They don’t trust big-spending incumbents. They don’t even trust conservative magazines, websites, and commentators who in their view run down conservative candidates.

Are there drawbacks to this approach? As one Mama Grizzly might say, “You betcha.” Ideology and values are vital, but qualifications matter too. So do local conditions and regional differences, where one size doesn’t fit all.

Finally, few RINOs are as brazen as Castle or Scozzafava. They now have learned to talk like conservatives and check the right boxes on conservative litmus tests even as they expand government once in power. The George Romneys have become Mitt Romneys, the George Bushes George Ws. Will conservatives be as demanding of them?

But for now, this much is clear: Grassroots conservatives picked Christine O’Donnell over Mike Castle, electoral consequences be damned. If it can happen in Delaware, it can happen anywhere.