WASHINGTON — Gun control advocates had told themselves this time would be different. It wasn't.
The two-decade deadlock that has gripped congressional efforts to act on gun control continued Wednesday as a measure to require more gun buyers to go through background checks was rejected in the Senate. With it sank the legislative effort to respond to the killings of 20 first-grade children and six educators in Newtown, Conn.
The background check proposal, negotiated by Sens. Joe Manchin III, D-W.Va., and Patrick J. Toomey, R-Pa., won the backing of 54 senators, a majority, but fell short of the 60 needed to overcome the Senate's procedural barriers.
Seven measures came to the floor. All failed. Included were a proposal to strengthen laws against gun trafficking, two Republican measures backed by the National Rifle Association that would have expanded the rights of gun owners and a measure by Sen. Dianne Feinstein, D-Calif., to ban high-capacity ammunition magazines and semiautomatic rifles considered to be "assault weapons." Feinstein's proposal lost heavily, getting only 40 "ayes."
For advocates of gun control, the vote against expanding background checks was a bitter defeat.
President Barack Obama, who made the issue a priority after Newtown, called the vote "a pretty shameful day for Washington" and accused the "gun lobby and its allies" of having "willfully lied about the bill."
Senators had no "coherent arguments" against the background check measure and had "caved to the pressure" from gun advocates, he said in the White House Rose Garden, flanked by family members of Newtown victims and former Rep. Gabrielle Giffords, D-Ariz. He vowed to continue pressing for new controls.
"I see this as just round one," he said.
Feinstein decried a "lack of courage" among her colleagues. "Show some guts," she demanded in a brief speech before the vote.
But the NRA and its allies hailed the vote. The background check proposal "would have criminalized certain private transfers of firearms between honest citizens," the NRA's chief lobbyist, Chris Cox, said in a statement.
Efforts to change gun laws have repeatedly run up against an intractable divide that pits members of Congress from urban states, mostly Democrats, against those, largely Republicans, who represent more rural states with large numbers of gun owners.
After the shootings at Sandy Hook Elementary School in December, gun control advocates pointed to polls that showed overwhelming support for background checks and briefly believed that public outrage over the deaths might change that stubborn political calculus. They focused on proposals to broaden the existing law on background checks. That issue marked the "sweet spot" in the gun debate, a change that would do considerable good and was politically feasible, the gun bill's chief author, Sen. Charles E. Schumer, D-N.Y., repeatedly said.
The current law, passed in 1993, requires people who buy guns from licensed dealers to go through a background check, but exempts sales outside that network, including those at gun shows and via the Internet. Federal officials say many sales bypass background checks and believe those sales are a primary source for guns used by gangs and other criminals.
But optimism faded in recent weeks.
As the gun control efforts began to gain ground in the Senate, the NRA and its allies waged a highly effective campaign to rally supporters. Expanded background checks would infringe on the rights of gun owners to sell their weapons to friends or neighbors, they warned. Records of sales could one day be used to form a national gun registry, they asserted, brushing aside that federal law — as well as an explicit provision of the Manchin-Toomey proposal — bars any such effort.
"The politics never changes on this issue," said former Rep. Richard A. Gephardt, D-Mo., who was majority leader the last time a gun bill passed Congress.
Whatever popularity gun control measures may have nationwide, a core of highly motivated voters, particularly in rural states, opposes them fervently. In the end, four Democrats from conservative states, Max Baucus of Montana, Mark Begich of Alaska, Heidi Heitkamp of North Dakota and Mark Pryor of Arkansas, voted against the background check proposal. All but Heitkamp face election next year.
Asked to explain his vote, Baucus said one word: "Montana."
On the Republican side, opposition to gun control and suspicion of Obama melded to solidify opposition to any new controls. When Manchin and Toomey reached their agreement last week, they discovered that few Republicans would sign on. In the end, only four, Toomey, Susan Collins of Maine, Mark Steven Kirk of Illinois and John McCain of Arizona, were willing to do so.
"It really comes down to identity politics," said Richard Feldman, president of the Independent Firearm Owners Association, a smaller gun-rights group that backed the Manchin-Toomey proposal.
"If Barack Obama says that the sun rises in the east, well, if I'm on the other side, I know it must be false," he said, adding, in a reference to the NRA's executive vice president, "and if Wayne LaPierre says the sun rises in the west, it must be true."