The Senate voted 54-46 in favor of the bipartisan amendment from Sens. Joe Manchin, D-W.Va., and Pat Toomey, R-Pa., to broaden background checks to all online and gun-show sales. However, the amendment required 60 votes for approval.
Speaking with four U.S. mayors during a Google+ Hangout, Biden said it was ironic that polls indicate "90 percent of Americans believe" federal background checks on firearms sales should be expanded, but gun legislation requires a super-majority for passage in the Senate.
"We're gonna get this eventually," Biden said, as he prepared to go to the Senate chamber to preside over the session. "If we don't get it today we'll get it eventually because the American people are way ahead of their officials."
He told the mayors participating in the event -- Karen Freeman-Wilson of Gary, Ind.; Stephanie Rawlings-Blake of Baltimore; R.T. Rybak of Minneapolis, and Steve Scaffidi of Oak Creek, Wis. -- U.S. mayors deal with gun violence from a vantage point unlike most others.
"You walk every day outside and you find gangbangers out there -- people who are injured by guns, people who are using guns to commit suicide," he said. "You go to the funerals."
Addressing the politics of the issue, Rybak said many elected officials "are afraid to take a tough stand because they are concerned it might mess them up in the next election."
He said public support for gun control legislation following the Dec. 14 massacre of 20 children and six staffers at Sandy Hook Elementary School in Newtown, Conn., will keep growing -- putting more pressure on elected officials to support what Biden called "rational basic gun safety initiatives."
"Do you want to know what kind of lobbying force is being built [by gun control advocates]? Do you think they'll be quiet if you ... choose to do nothing?" Rybak asked, warning, "Any person in Congress who chooses to wimp out on this thing" will pay a price in coming elections.
Notable deaths of 2014 [PHOTOS]