Enough Republican senators ceded to mounting political and public pressure to pave the way for a debate on the first major piece of gun-control legislation to be considered by Congress in two decades.
The Senate voted 68 to 31 to head off a threatened filibuster by a group of conservative, Tea Party-leaning Republicans, who wanted to block tighter gun control laws even being debated in the chamber.
Leading Republicans in the Senate, including John McCain of Arizona and Lindsey Graham of South Carolina, voted to move forward on the debate as 16 GOP senators joined 50 Democrats and two Independents to defeat a Republican filibuster, creating some hope that the measures may pass.
Democratic senators Mark Pryor of Arkansas and Mark Begich of Alaska, who face traditional Republican-leaning electorates in their states, voted with Republicans against the gun controls being debated.
The victory was a first, cautious step towards meeting US president Barack Obama's call for stronger gun control laws to be at least voted on in the aftermath of the second-worst school shooting in US history at the Sandy Hook Elementary School in Newtown, Connecticut that left 20 children and six adults dead.
The support of the Republicans was helped by a compromise deal on background checks on gun purchases brokered by NRA supporters Joe Manchin, a conservative Democrat from West Virginia, and his friend, Pat Toomey, a Republican from Pennsylvania known for his conservative stance on fiscal matters.
Their bipartisan deal, which would extend background checks to cover online sales of guns and unlicensed firearms dealers at gun shows, saved new gun laws sought by the White House and gun control groups from defeat before they could even be considered by lawmakers.
Bully pulpit
Republican opponents, led by senators Rand Paul and the minority leader in the Senate Mitch McConnell, were posturing over recent weeks to keep any legislation off the floor of the Senate but Mr Obama intensified pressure on Congress using the bully pulpit to win around pro-gun advocates in the chamber.*
First lady Michelle Obama followed an emotional speech by the president in Connecticut by referring to the murder of 15-year-old Hadiya Pendleton in Chicago in a speech in her hometown.
Her personal intervention was an unusual move by the White House by using Mrs Obama’s popularity to support a major policy issue in a major shift from a largely apolitical role.
Vice-president Joe Biden, who is spearheading the White House's drive for gun-control measures, kept up the pressure by appearing on morning television yesterday ahead of the Senate vote, saying that the public has been "so far ahead" of the politicians on the issue of gun control.
Victims of gun violence joined the lobbying efforts as families of those killed at Newtown in December made representations to legislators prior to Thursday’s vote.
Even if the gun legislation passes the Senate, the measures will face an even more difficult challenge passing the lower House of Representatives where Republicans sit in the majority.
Republican congressman Paul Ryan of Wisconsin, Mitt Romney's running mate in the presidential election, said he was carefully watching the legislation, particularly the Manchin-Toomey compromise.
Ryan urged caution that Congress not to rush gun controls and avoid considering related issues such as mental illness, which the National Rifle Association has cited as the main reason for gun violence.
'Root cause'
"We need to look at the root cause of these problems, and I hope that we can do that – I am worried that we won't," he said.
In a reflection of the pressure on Republicans, Toomey came under pressure from 75 Republican legislators in his home state of Pennsylvania, who oppose additional federal gun laws, to explain his agreement with Manchin.
A new NBC/ Wall Street Journal poll showed support for more stringent gun laws falling since Mr Obama made the issue a central plank of his second-term agenda in his state of the union speech in January.
Some 55 per cent of voters were in favour of tighter gun controls, down six percentage points. Reflecting the political battle ahead in Congress, the split among voters breaks down starkly along party lines; some 82 per cent of Democrats want stricter controls compared with just 27 per cent of Republicans.
*This article was amended on April 12th 2013 to correct a factual error
