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.