WASHINGTON — How big a deal was Marco Rubio’s speech to CPAC Thursday? If you are asking, as former President George W. Bush did jokingly the other day, “Who the hell is Marco Rubio?” you probably won’t be for long. Rubio is the 38-year-old former speaker of the Florida House and a conservative challenger to the state’s Republican governor, Charlie Crist, in the GOP Senate primary. If you are asking, what is CPAC? you probably aren’t a conservative Republican. CPAC, the Conservative Political Action Conference, is, for several days every winter, the epicenter of the conservative movement; Ronald Reagan spoke before the group a dozen times.

So Rubio’s keynote address served as his national coming-out party — an event so important that not only did Rubio post a video preview on the importance of opposing the Obama agenda, but Crist issued a faux advance text of Rubio’s speech. Crist’s Rubio parody depicted him as a “cover boy” lobbyist who talks conservative but acts pragmatic (my word, not Crist’s) on issues from immigration to climate change to stimulus spending. Which is, apparently, bad, at least if you are trying to win a Republican primary.

At CPAC, Rubio made Sarah Palin look oratorically challenged. When some in the ecstatic crowd broke into a chant of “Marco, Marco,” Rubio flashed his winning smile and said, “I’m always afraid someone’s going to start screaming ‘Polo’ and then it will ruin the speech.”

He wove his only-in-America background — son of Cuban immigrants who fled Castro, his father working 16-hour days, his mother a K-Mart stock clerk — into a larger narrative of American exceptionalism. The 2010 election, he argued, is a “referendum on the very identity of our nation,” with the choice boiling down to this: “Do I want my children to grow up in the country that I grew up in or do I want them to grow up in a country like the one my parents grew up in?”

Rubio handed out more red meat than a butcher before a snowstorm. President Obama and the Democrats, he argued, are “using this downturn as a cover not to fix America but to try to change America,” implementing “statist policies” that would “fundamentally redefine the role of government in our lives and the role of America in the world.” Voters want political leaders to work together, he said, but only for the right results. “The U.S. Senate already has one Arlen Specter too many,” he said to cheers. “America already has a Democrat party. It doesn’t need two Democrat parties.”

If Evan Bayh was watching, the Indiana Democrat would have thought he made the right choice in deciding not to run again.

As Rubio was speaking, Obama was preparing to issue an executive order on what I worry may turn out to be the fiscal responsibility commission to nowhere: It will not work without good-faith Republican participation, and that does not seem to be forthcoming. Consider Rubio’s fiscal prescription: “Reduce tax rates across the board.” “Abolish taxes on capital gains, dividends, interest.” “While we’re at it, let’s eliminate the one on death, too.” “Significantly lower the corporate tax rate.” “And, while we’re at it, undertake serious measures that show we’re serious about getting control of our national debt.”

This is not a prescription for responsible governing.

Rubio more than fulfilled the expectations that he is a rising star of the Republican Party. He is young, attractive and appealing; his life story could not be more inspiring. From 30 points or more back in the polls, he has moved ahead of Crist: 46.9 percent to Crist’s 39.7 percent, according to the latest average from Pollster.com. Rubio’s message dovetails perfectly with the take-our-country-back fervor of the tea-party movement, without some of the anger. He is someone to watch — and, for those who still believe in the possibility of centrist, bipartisan solutions, to fear.