WASHINGTON (REUTERS) - An assault weapons ban sought by President Barack Obama ran into serious trouble on Tuesday when Majority Leader Harry Reid acknowledged there was not enough support for it in the US Senate.
It was the latest blow to the White House's gun control plans which are fading as Republicans and even some Democrats baulk at taking on the powerful gun lobby.
Less than half of the Senate backs the assault weapons ban, Mr Reid said, which would condemn it to failure when gun control legislation comes to the floor of the chamber next month.
Prohibition on the sale of assault weapons was always the most controversial element of Mr Obama's attempt to stem gun violence since December's massacre at a Connecticut school where 26 people died.
Backed by a lobbying campaign from the National Rifle Association, many lawmakers argue that bringing back a ban that ran out in 2004 infringes Americans' constitutional right to bear arms.
Mr Reid told reporters that the bill by Senator Dianne Feinstein to renew the ban "has less than 40 votes" in the 100-member chamber.
Other gun control efforts like universal background checks on people buying guns are also struggling in Congress, despite public anger at the Connecticut shooting and other massacres.
Along with immigration reform, gun control is a top domestic policy priority for Mr Obama at the start of his second term, and White House Chief of Staff Denis McDonough refused to concede defeat on the assault weapons ban.
"We're going to work on this. We're going to find the votes, and it deserves a vote. Let's see if we can get it done," Mr McDonough told CNN.
Senators are likely to vote on the ban in April as an amendment to other gun control legislation, but its chances of success are now virtually nil. Sixty votes would be needed to clear an anticipated Republican procedural roadblock.
Democrats control the chamber 55-45, meaning that a number of Mr Reid's fellow Democrats have made it clear that they intend to oppose renewing the ban.
Other Democrats who support outlawing assault weapons sales appeared resigned.
Representative Carolyn McCarthy of New York said she would be disappointed if Congress refused to renew the prohibition.
"But there are many things that can be done to reduce gun violence - including restricting high-capacity magazines, strengthening background checks, stopping traffickers and improving school safety," Ms McCarthy said.
The ban on assault weapons like the one used in the Connecticut shooting is one of four gun control bills that the Democratic-led Judiciary Committee has sent to the full Senate.
A proposal to provide funding for school security is now the only gun violence measure sure to pass. Two others face an unclear future.
An effort to expand background checks on gun buyers has run into opposition from Republican lawmakers who fear that could be a first step toward registering gun owners.
The other plan would make it a federal crime to purchase a firearm on behalf of someone who is barred from owning one, but critics of the measure complain that it is difficult for a gun seller to know who is allowed to buy a weapon and who is not.
Mr Chris Cox, executive director of the Institute for Legislative Action, said there was plenty to be done to control gun violence without weapons bans.
"We look forward to working with members of Congress on securing our schools, reforming our mental health care system, and prosecuting criminals to the fullest extent of the law - proposals that will make a real difference," he said.
Mr Reid said he would bring gun control legislation to the floor of the Senate in April. A bill which would put aside US$40 million (S$50 million) a year for 10 years to make schools safer has the best chance of winning the 60 votes needed to pass.
The ban on assault weapons includes putting a limit on high-capacity ammunition clips but that also looks likely to fail.