President Barack Obama has barnstormed the country promising action on gun control legislation, and on Wednesday the Senate acted — to vote down the heart of the bill.

The president is vowing that the fight for tighter gun control measures is not over. But Obama’s cache in Congress has always been low, and it appears his strategy for continuing to push the issue largely rests on something that has proved elusive to him in other recent policy fights, including this one: public pressure.

As relatives of the victims of December’s Newtown, Conn., shooting looked on from the Senate gallery — and someone shouted “Shame on you!” — the chamber fell five supporters short of the 60-vote threshold on a bipartisan background check bill that would end the gun show exemption and expand checks to online sales. The Senate also failed to adopt new limits on high-capacity ammunition magazines, and it declined to renew an expired assault weapons ban.

Despite public declarations of optimism from supporters on background checks, sources said privately that the Senate may never be able to pass those items. Republicans and many red-state Democrats — four of whom defected on the background check bill — still fear the repercussions of crossing the National Rifle Association.

Vice President Joseph R. Biden Jr., who was on the Hill for the vote, quoted a member acknowledging that Americans overwhelmingly support background checks. “‘Ninety percent thinks it’s a good idea but they’re not going to vote for me or against me because of how I vote on this,’” Biden quoted the member as saying. He did not name the lawmaker.

Biden later said members complain that they have to look the NRA in the eye, but he noted that they are going to have to look gun violence victims in the eye, too.

But that line of persuasion clearly didn’t work. Neither did the White House’s full-court press in the final 24 hours before the Senate votes began. Obama picked up the phone and called senators personally and Biden, in addition to lobbying members, presided over the vote on a background check deal brokered by Democratic Sen. Joe Manchin III of West Virginia and Republican Sen. Patrick J. Toomey of Pennsylvania.

“I hope to God that there’s 60 people up there that have the courage to stand up and understand that this doesn’t take that much courage,” Biden said in an online chat moments before leaving for the Capitol.

The president gave an impassioned speech in the Rose Garden shortly after the background check provision failed. Saying gun rights groups like the NRA “willfully lied” about the Manchin-Toomey agreement, Obama suggested that some senators caved to the pressure and looked for any excuse to vote against it. But even as he pronounced the Senate vote “a pretty shameful day for Washington,” he also said it was “just round one.”

He called on Americans to build sustained pressure for enhanced background check legislation, among other gun control provisions. “Sooner or later, we are going to get this right,” Obama said.

With the odds stacked against them, however, it’s unclear whether public pressure and hope will be enough to propel the White House to a legislative win on guns, especially given that an issue more politically appealing to both sides — immigration — is waiting in the wings.

So is there anything the president can now do to keep the promises he made to aggrieved people in Newtown, Conn., Aurora, Colo., and Chicago?

“I’m not sure what more the president can do, having persuaded 90 percent of the American public to support the heart of this bill, which is background checks,” said Sen. Christopher S. Murphy, D-Conn., who has become a leading voice on the issue since the Sandy Hook Elementary School shooting in his state. “The fact is, senators are simply not listening to their constituents. And I’m not sure what more the president can do.”

White House Press Secretary Jay Carney was cagey with reporters before the vote Wednesday, saying he would not detail what would come next. He would not acknowledge that the Democrats’ argument for new gun laws, which has been pegged mostly to emotional reaction, seems to weaken with the passage of time.

“We believe … that there is a path, a very difficult path, but a path to get to 60,” Carney said. “What’s complicated about the fact that 90 percent of the American people want this done and yet a substantial percentage of the Senate at least seems to disagree with the vast majority of the American people, to disagree with the vast majority of the people of their states?”

Emotional pleas were not enough of a legislative strategy, though. Not only did the president’s speeches on the road ring hollow to senators in the Capitol, but members were not even receptive to pleas from their own.

For example, former Rep. Gabrielle Giffords, D-Ariz., attended a ceremony Tuesday to dedicate a Capitol Visitor Center room to her slain staffer. She was joined not only by gun control supporters such as Biden and her husband, Mark Kelly, but also by Arizona Republican Rep. Jeff Flake.

Flake, a friend of Giffords’ who drove to Tucson from his Mesa home when she was shot in 2011, had just announced he wouldn’t support the Manchin-Toomey bill. Giffords and Kelly, even with their personal connection and new money-based influence, couldn’t change his mind.

Though many Republicans balked at the background check deal, saying it would create a federal gun registry that the legislation explicitly prohibited, not every GOP senator was buying their colleagues’ talking points.

“You may not win today … but I will say that you did the right thing,” Sen. John McCain, R-Ariz., said to Manchin and Toomey on the floor. “And it’s been my experience as a senator in this body who has not always done the right thing, that doing the right thing is a reward within itself.”

Still, Reid announced Wednesday after the failure of multiple gun control amendments that the Senate would move on to other business on Thursday. He did preserve his right to bring the measure back up at a later date, however.

A disappointed Senate Majority Whip Richard J. Durbin, D-Ill., said the Senate could return to the gun violence issue if or when members feel political heat over opposing the measure.

“I don’t think this is the end of it,” Durbin said. “It used to be that the NRA would win, we’d wait for another few years and think about it all over again.”

Steven T. Dennis and Humberto Sanchez contributed to this report.