By David Lawder
WASHINGTON (Reuters) - The U.S. Senate will make its strongest push in years to tighten gun controls on Monday, voting on four proposals a week after the Orlando shooting massacre prompted new calls to keep firearms away from people on terrorism watch lists.
But while the deadliest mass shooting in modern U.S. history has spurred quick action in Congress, none of the bills is expected to achieve the 60 votes needed for passage in the 100-seat chamber, as Republicans and Democrats have not been able to reach consensus on the extent of any new restrictions.
The proposals aimed at strengthening background checks for gun purchases will come as amendments to a Justice Department spending bill.
While similar bills failed after mass shootings at an elementary school in Newtown, Connecticut in 2012 and a conference center in San Bernardino, California in 2015, some senators insist the politics over gun control are shifting, with national security looming larger in the debate.
The Orlando gunman, Omar Mateen, pledged allegiance to the militant group Islamic State, or ISIS, as he killed 49 people in a gay nightclub, authorities said.
"I admit that the background checks bill is going to be tough to get 60 votes on, but we still have hope that we can get Republicans to support the bill, stopping terrorists from getting weapons," Senator Chris Murphy, a Connecticut Democrat, told ABC's "This Week" on Sunday.
In the Republican-controlled Senate, Murphy led fellow Democrats in 15 straight hours of floor debate last week to demand action on gun control, a move he said "helped galvanize an entire country around this issue."
A Reuters/Ipsos poll conducted last week found that 71 percent of Americans favor at least moderate regulations and restrictions on gun sales, including eight of 10 Democrats and six of 10 Republicans. That compared with 60 percent in late 2013 and late 2014.
Congress has not passed new gun restrictions since a 2007 expansion of the government's automatic background check database to include individuals with a history of mental illness and felons. The United States has more than 310 million weapons, about one for every citizen.
A Democratic congressman on Monday called on House of Representatives Speaker Paul Ryan, a Republican, to schedule a vote on a 'no fly, no buy' bill this week before lawmakers go on vacation on Friday.
"Paul Ryan has an obligation to at least put that up for a vote. And I believe that if he did, it would pass," U.S. Representative Steve Israel of New York told CNN.
(Additional reporting by Doina Chiacu; Editing by Mary Milliken and Jeffrey Benkoe)