WASHINGTON – Prominent gun-rights advocates in Congress are now calling for a national discussion about restrictions to curb gun violence, signaling that the horrific shooting at a Connecticut elementary school could be a tipping point in a debate that has been dormant for years.

“Everything should be on the table,” West Virginia Sen. Joe Manchin declared Monday. He is a conservative Democrat, avid hunter and lifelong member of the National Rifle Association. Republican Sen. Chuck Grassley of Iowa proposed a debate not just about guns but also about mental issues.

White House officials said President Barack Obama would make preventing gun violence a second-term policy priority. But it was unclear what Obama would pursue or how, and aides said stricter gun laws would be only part of any effort.