Marco Rubio stepped onto the stage at CPAC knowing that part of his job was to jolt conservatives while telling them that they'll have to support the Republican nominee for president even if it's not exactly who they want.

The sprawling ballroom at the Marriott in northwest Washington, D.C., had filled up to hear the hero of the conservative movement speak. He was introduced by someone who called him a future president. He got a standing ovation before he even said a word.

And when Rubio spoke, he won them over. "He is a terrible president," Rubio said of President Obama as the crowd erupted in cheers. "He cannot run on his record," and he "has decided to pit Americans against each other," the Florida senator said.

Noting that the Republican candidates have tried to portray themselves as the most like Ronald Reagan, Rubio jabbed that "the Democrats never fight over who's more like Jimmy Carter."

Rubio said he loves the GOP primary, and he told the people at the Conservative Political Action Conference not to "let the media convince you" that the process will divide the Republican Party. Instead, he said, all Republicans will come together behind the nominee (which many conservatives fear will be Mitt Romney, the moderate choice).

"You know that, right?" Rubio asked rhetorically.

Romney's triple loss to Rick Santorum, another conservative, in this week's three voting contests has sparked the storyline that Republican voters are simply not excited enough to rally behind the front-runner.

Despite Rubio's plea to the conservative movement, it's unclear whether the message got through. When one of the first speakers at CPAC ran through the list of candidates, Romney got only tepid applause, while Santorum's name brought about whoops and cheers.

Thomas Beach, an Army veteran from Moulton, Ala., lamented after Rubio's speech that the "Republican establishment" could endanger the party if it continues to "push people like Romney."

"Rubio reflects what I believe in my heart," Beach said. "I'm a conservative. I'm the base."

Rubio, a young, telegenic senator who continuously has been on observers' short lists as a nominee for vice president, spent most of his speech lambasting Obama on Medicare, energy, the military and the White House's recent contraception mandate.

He also made a joke about Teleprompters that went over pretty well. He said it's hard to find them in Washington because one person is hogging them all, meaning Obama.

"He says what most of us think," said Polly Sullivan, a clinical researcher from Loveland, Ohio. "I hope that more people can hear him."