WASHINGTON (MarketWatch) -- A bipartisan amendment that would expand background checks for gun-buyers failed in the Senate on Wednesday, dealing a blow to backers of gun-control legislation. The amendment, offered by Republican Sen. Pat Toomey of Pennsylvania and Democrat Joe Manchin of West Virginia, got 54 "yes" votes, short of the 60 required for passage. The amendment would have required background checks for sales at gun shows and online.