* Emotional, weeks-long debate ahead on gun control
* Bill still faces significant hurdles
The U.S. Senate cleared the way on Thursday for an emotional, weeks-long debate on proposals to curb gun violence, rejecting an effort by conservative Republicans to block consideration of gun-control legislation prompted by December's Connecticut elementary school massacre.
The Senate voted 68-31 to open debate on President Barack Obama's proposals to expand background checks for gun buyers, tighten restrictions on gun trafficking and increase funding for school security.
The Senate easily cleared the 60-vote hurdle needed to break a Republican filibuster on a bill that has sparked intense lobbying on both sides, including families of the Connecticut victims as well as the powerful gun lobby the National Rifle Association.
The legislation still faces many hurdles, including a weeks-long debate in the Senate featuring many amendments that could make the bill unacceptable to senators who now support it. And if it clears the Senate, it would face a tough reception in the Republican-led House of Representatives.
No major gun legislation has passed the U.S. Congress since 1994.
"It is a really important start," Democratic Senator Christopher Murphy of Connecticut said before the vote, displaying photos of some of the victims of the Dec. 14 massacre of 20 children and six adults at an elementary school in Newtown, Connecticut.
The vote to proceed with debate came a day after a compromise agreement on background checks between prominent defenders of gun rights from each party - Democrat Joe Manchin of West Virginia and Republican Patrick Toomey of Pennsylvania.
That agreement to expand criminal background checks of gun buyers to include commercial sales made at gun shows and online was expected to boost bipartisan Senate support for the measure.
The expanded background checks, a provision that polls show has the support of up to 90 percent of Americans, will be the first amendment offered in debate and appears to be Obama's best hope for achieving meaningful gun-control legislation.
But Obama is unlikely to get some elements of gun control that he has advocated, including a ban on rapid-firing "assault" weapons like the one used in Connecticut and limits on the capacity of ammunition magazines. Amendments to add those provisions to the bill being considered by the Senate appear to have a slim chance of winning on the Senate floor.
Many Republicans and some Democrats have objected to the gun-control proposals as an infringement on their constitutional right to own guns.
"This bill is a clear overreach that will predominantly punish and harass our neighbors, friends and family," said Republican Senate Leader Mitch McConnell of Kentucky, who joined the effort to block debate on the bill.