RICHMOND, Va. -- Vice President Joe Biden spoke Friday to Virginia leaders who responded to the worst school shooting in the nation’s history as the White House begins its try to sell America on a contentious gun control proposal.

Biden spoke behind closed doors for more than two hours with nearly a dozen elected officials, law enforcement and mental health professionals about state efforts following the 2007 Virginia Tech shooting, which left 33 people dead, to make background checks for gun purchases more comprehensive.

“We have an obligation to act – not wait,” Biden told reporters after the event at Virginia Commonwealth University. “There’s certain things we know with certainty will diminish the prospects of what happened in Virginia Tech or what happened in any of these other mass shootings.”

The White House is returning to a familiar tactic – pressuring Congress through a public relations campaign – as it tries to implement the nation’s most aggressive gun control plan in generations in the wake of a slaughter in Newtown, Conn., that claimed the lives of 26 victims, including 20 elementary school children.

President Barack Obama employed the same tactic last month when trying to sell his solution to avert a series of spending cuts and tax increases, and in 2011 on issues ranging from the extension of a payroll tax cut to college loan rates.

This time, he will be aided by Organizing for America, his former campaign committee, which has been transformed into an organization designed to reach millions of Americans through ads, phone calls, door-knocking and events.

But the president’s package, which includes proposals for banning assault weapons, limiting the capacity of ammunition magazines, requiring background checks on all gun purchases and spending millions more dollars on training, research and counseling, will be one of his toughest campaigns.

Much of the sweeping package needs approval from a divided, unenthusiastic Congress. Obama must build popular support across an also divided nation, even in states that backed his rival, Republican Mitt Romney, in last year’s election, and in states where owning guns are part of a way of life.

“This is going to be a geographic issue, not a party issue,” Republican political consultant Nachama Soloveichik said. “I know people like to paint these issues as Republican or Democrat, but some issues really are geographic, and this is one.”

Virginia backed Obama for president in 2008 and 2012, but it is primarily run by Republicans who have been friendly to gun rights proposals. Just last year, lawmakers lifted a 19-year-old limit that only allowed the purchase of one gun per month in the same state that is home to the powerful National Rifle Association.

In recent years, the bustling suburbs in northern Virginia, outside Washington, have tended to skew to residents supporting liberal stances, including gun control. But Biden chose instead to travel deeper into the state, to the capital city of Richmond.

A recent Gallup poll showed that Americans across the nation back Obama’s proposals. The support is highest, 68 percent, in the East, and about even in the other regions: the Midwest, 50 percent; the South, 49 percent; and the West, 47 percent.

“This is not a true divided nation, but clearly there is a tilt,” said Gallup Editor Frank Newport.