President Obama blasts Senate for blocking legislation to extend universal background checks.

At the White House, Obama stood with Vice President Joe Biden and former Arizona congresswoman Gabrielle Giffords, who survived a shooting two years ago. They were surrounded by the parents from Sandy Hook elementary who have been lobbying senators in private meetings for the last week.

Barden, whose youngest child, Daniel, was killed Dec. 14, said that when he and other parents arrived in Washington, D.C., senators were prepared to filibuster, and the fact that gun legislation was brought to a vote is a success.

"We are in it for the long haul," Barden said Wednesday night. "I think the attitudes of the vast majority of Americans are there."

The background check provision was one of seven amendments to a gun control bill that the Senate rejected Wednesday for lack of the required 60 votes; the overall bill hasn't come to a vote.

One of the amendments, introduced by Sen. Richard Blumenthal, D-Conn., would have banned large capacity ammunition magazines such as the 30-round magazines used by Lanza at Newtown. The vote was 54-46 against Blumenthal's measure.

The Senate will continue voting on Thursday, but the failure of the significant measures spelled overall defeat for gun control advocates.

Blumenthal and his fellow Connecticut senator, Democrat Chris Murphy, told reporters in an evening conference call that they would keep fighting.

"Today was heartbreaking, one of the saddest and shocking days of my life in public service, maybe my whole career," Blumenthal said. "The hardest part of the day was really deciding how to explain to families that … 54 senators could vote for a measure and yet have it fail. … What will change is the American people telling their senators they are aghast and outraged at the result."

Murphy said: "I don't know what's worse, that the NRA lied or that they got away with it," echoing the president.

Murphy was one of the advocates who vocally wanted to "demand a vote" for Newtown, in order to get senators on the record as supporting or opposing gun restrictions. Responding to Wednesday's results, Murphy said: "There's going to be a price to be paid for senators who voted the wrong way."

Rep. Elizabeth Esty, D-5th District, who represents Newtown, criticized the Senate proceedings, saying: "The families of Newtown … deserve a real vote, not procedural maneuvers."

Gov. Dannel P. Malloy, who has met with Obama and Biden about state and federal gun control efforts, said Wednesday: "When the Senate cannot come together on an issue that is supported by the vast majority of Americans, there is little to no hope that common sense will prevail. The members who voted against this proposal should be ashamed of themselves."

Courant staff writer Matthew Sturdevant contributed to this story.