Joe Manchin, D-W.Va., and Pat Toomey, R-Penn., have talked about reviving it since the Parkland shooting. Facing opposition from the NRA, the bill secured 54 votes in 2013, but fell short of the 60 votes needed to overcome a filibuster. One study by researchers at Northeastern University and Harvard University estimated that 22 percent of gun sales occur without a background check under the current system. Manchin-Toomey, introduced in 2013 after the Sandy Hook attack, would have required background checks on online and gun show sales of firearms, closing what critics call the "gun show loophole," while exempting private sales between friends and family. The bill also would provide more funding to states to improve their background check system and penalize political appointees at federal agencies if they don't take steps to maintain their records. It aims to correct failures in the National Instant Criminal Background Check System that allowed the shooter who killed 26 people at a church in Sutherland Springs, Texas, in 2017 to legally buy a gun despite a domestic violence conviction in the Air Force that should have come up in a background check if it had been properly updated. Like a lot of proposals being discussed, it was crafted as a response to a prior shooting. The White House has signaled its interest in the bill and the NRA is not opposed, removing two big obstacles to passage Senate leaders are planning to move ahead with a vote. The first is the Fix NICS Act, which was introduced last year by Senate Majority Whip John Cornyn, R-Texas, and Sen. There are several major bipartisan bills drawing renewed attention in the Senate this month that aim to expand background checks for gun sale. Here's a look at some of the biggest ideas that President Donald Trump and lawmakers have put forward, what they would do, and their chances of being put in place.