(Getty Images)

Vice President Joe Biden is not letting the gun-control issue rest. At a speech in Las Vegas Friday at the U.S. Conference of Mayors' annual meeting, Biden said that "at least five senators" who initially opposed background checks have sought him out for an opportunity to change their votes.

"We're in an effort to see how we can provide another opportunity for the people who voted no" on universal background checks, which failed in the Senate in April. "That's the hardest thing for a politician and we need to provide them a rationale. We will get to this eventually."