WASHINGTON — With shouts of ‘Shame on you!’ echoing in the chamber, the U.S. Senate failed to muster sufficient support Wednesday for a gun-buyer background check bill that’s supported by nearly 90 percent of Americans.

It also voted down other key measures and counterproposals, defeating a string of amendments in a series of procedural votes that likely doomed any major legislation to curb gun violence.

The background check measure — painstakingly crafted by the bipartisan duo of Sens. Joe Manchin (D-W.Va.) and Pat Toomey (R-Pa.) — was seen as the key to passing the first legislation in decades to address the sorts of mass slaughters that so recently horrified the country in Newtown, Conn., where 20 children and six educators were gunned down at an elementary school, and in Aurora, Colo., where 12 people were killed in a theater.

The amendment failed 54 to 46, falling short of the 60-vote threshold needed to break a filibuster. That failure upset anew victims of the Sandy Hook shootings and other slaughters who watched from the Senate gallery.

‘Shame on you!’ shouted two women in the gallery after the vote. One was Patricia Maisch, who grabbed the third clip from the gunman who opened fired at then-Rep. […]