For decades, Republicans have struggled to find the balance between ideologically pure conservatism and more electable moderation. The sunny, optimistic Ronald Reagan who ran for president in 1980 was not the 1960s Reagan who railed against ``socialist'' Medicare. Once in office, the conservative icon raised taxes, ballooned the deficit, bailed out Social Security and granted amnesty to illegal immigrants.

Such is the difference between ideology and governing.

The Marco Rubio-Charlie Crist U.S. Senate battle in Florida offers a fresh glimpse into that dichotomy. The race pits conservatism as presented in the post-Goldwater era -- in the friendly face of Reagan, the ``compassionate conservatism'' of George W. Bush (before he got down with the whole Dick Cheney/Iraq invasion/domestic spying/torture thing) or the bonhomie of Florida's once high-flying governor -- against the blunt, back to the future, Goldwater-style conservatism that some in the GOP are increasingly offering to the public, no chaser. This is the 2010 conservatism pushed by the tea party movement, conservative media (from Fox News to talk radio to RedState.com) and media-activist hybrids like Glenn Beck, plus a growing list of congressional hardliners like South Carolina Sen. Jim DeMint and Medicare privatization proponent Rep. Paul Ryan of Wisconsin.

Up to now, Rubio has had it both ways. He pals around with right-wing rainmakers like DeMint and the Club for Growth but keeps their shared belief in Wall Street-invested Social Security accounts out of his campaign stump speech. He channels tea-party horror over stimulus money he, too, would have accepted if he were still Florida House speaker.

He panders to the race-baiting Tancredo fringe about not counting ``illegals'' in the U.S. Census though doing so would deliver a fiscal gut punch to the state he wants to represent.

He tells a Christian organization that Roe v. Wade should be overturned, knowing full well it didn't happen when Republicans controlled all three branches of the federal government because they know outlawing abortion would spark 50 state civil wars between the GOP and a majority of women.

And he rails about government's carelessness with ``the people's money'' after spending the ``donor people's'' money on himself when his Florida Republican Party American Express card was burning a hole in his wallet.

And then, along came Jim Bunning.

By stalling a Senate vote on extending unemployment benefits and COBRA to scores of Americans, with a ``tough s---'' kiss off to boot, the bizarre Kentuckian ripped the veil off the real-world consequences of the common tea-party cry: ``Stop spending!'' His filibuster was a stop payment that included 2,000 immediate job furloughs, hundreds of millions of dollars in transportation work stoppages for states, a 21.2 percent cut in Medicare reimbursements for doctors and the potential for 400,000 Americans, including 49,600 Floridians, to lose their only means of life support in a week's time.

Bunning also gave Rubio the opportunity to stand up for his principles and stand with fellow conservatives like Arizona Sen. John Kyl, who voiced a truth often heard among tea partiers and Libertarians but rarely voiced out loud by elected Republicans: that the right believes unemployment benefits make people lazy. (The ``principled'' Mr. Kyl later voted for the extension.)

Bunning also gave Rubio the chance to side with the Kentucky Tea Party, the two candidates vying to replace Bunning (including Ron Paul's son Rand), with RedState and Rush Limbaugh and the other supporters of Bunning's demand to ``pay for'' the bill first. Never mind that Bunning awkwardly voted against pay-as-you-go rules in the Senate and has voted for unpaid-for tax cuts for the rich, prescription-drug subsidies for insurance companies and the Iraq war.

Rubio could have backed up his new BFF DeMint, who called Bunning his ``hero.'' Or, he could have walked away from his right-wing supporters and stood up for unemployed Floridians, saying it was time to put his state ahead of ideology.

He did neither, and instead, remained stubbornly silent, waiting out the Bunning crisis while Rubio's spokesman promised me to try to get a response as to whether Rubio supported Bunning. Bunning ended his filibuster Tuesday night. I'm still waiting for Rubio to comment.

It was both a demonstration of political cowardice and a tacit admission of the primary contradiction in Rubio's brand. He wants to be a right-wing hero, but he would just as soon avoid the real-life consequences of the things he says he believes.

Joy-Ann Reid is a writer and documentary producer in South Florida.