"Gabby and I are excited to hit the road this summer and meet so many of the great Americans who are standing with us to fight for common-sense solutions to prevent gun violence and protect our rights."

The tour includes visits to states represented by centrist senators who voted against a background check amendment in April, effectively killing gun-control legislation championed by the president in the aftermath of the Newtown, Conn., elementary school shooting. That bill would have required background checks on weapons purchased over the Internet and at gun shows, but fell five votes short of the 60 needed for passage.

Sens. Mark BegichMark BegichThe future of the Arctic 2016’s battle for the Senate: A shifting map Trump campaign left out of Alaska voter guide MORE (D-Alaska) and Heidi HeitkampHeidi HeitkampNorth Dakota rep under consideration for Energy post Five things to watch in Dakota Access pipeline fight Dem senator had 'constructive' talk with Trump MORE (D-N.D.) have been criticized by gun control groups for their "no" votes, as has Sen. Kelly AyotteKelly AyotteJuan Williams: McConnell won big by blocking Obama Battle brews over Trump’s foreign policy Battle for the Senate: Top of ticket dominates MORE (R-N.H.).

At a gun event earlier this month at the White House, Vice President Biden predicted that political pressure would force some elected officials in the upper chamber to reconsider.

"I know for a fact some of them wonder now if that was a prudent vote," Biden said.

"The country has changed," he continued. "You will pay a price, a political price for not getting engaged and dealing with gun safety."