President Obama on Thursday mobilized the massive campaign operation that twice helped elect him as part of an effort to pressure Congress to pass his gun control proposals.

Obama for America has been virtually silent since the November elections. But the president revived the grassroots organization to help convince Americans to back his call for a ban on assault rifles and high-capacity ammunition magazines and push for universal background checks for gun buyers.

Early Thursday, Obama campaign manager Jim Messina sent emails to millions of supporters urging them to "stand with President Obama" on gun control, and later, Vice President Biden previewed the campaign-style blitz the White House will initiate.

"We're going to take it to the American people," Biden told a gathering of U.S. mayors Thursday. "We're going to go around the country making our case and we're going to let the voices, the voices of the American people be heard."

It's not certain that Obama can reclaim and invigorate the national network of backers that propelled him to victory over Republican Mitt Romney last year. And while his supporters did rally around the president in the fight for middle-class tax cuts, guns are a more polarizing issue.

"The gun rights side has always had a major advantage with mobilization; the use of [Obama for America] is a potentially very important development," said Kristin Goss, a political scientist at Duke University and author of "Disarmed: The Missing Movement for Gun Control in America." "But I still want proof the [Obama campaign team] can create intense, sustained pressure."

Obama for America is set to meet Sunday with supporters gathering in Washington for the president's inauguration and will continue working to shift the organization's focus from electing a president to pushing a legislative agenda.

Still, some questioned whether the grassroots organization can help usher gun control measures through a Congress that has repeatedly rejected such restrictions over the last two decades.

"The president has always been more successful selling himself than his policies," said Frank Donatelli, who was President Reagan's political director. "They have a big hill to climb. Most views on this issue are very well-known."

The online petition Messina launched Thursday sets the stage for a major clash between two of the most influential organizations in politics. The Obama campaign compiled millions of email addresses during Obama's two presidential runs. Meanwhile, the National Rifle Association, the nation's most powerful gun rights lobby, boasts more than 4 million members.

The NRA promised its members "the fight of the century" over Obama's gun proposals. And congressional Republicans have so far shown little appetite for any of the president's recommendations.

"To succeed on any of his proposals, the president needs to get political pressure out of Obama for America and like-minded groups," Democratic strategist Doug Schoen said. "He wasn't able to do so on health care. We'll see if he can do it on gun violence prevention."