Obama has made enactment of greater curbs a priority on his domestic agenda in the months since the massacre at Newtown, making several trips outside Washington to try and build support. Last week, he traveled to Connecticut, and he invited several parents to fly back to Washington with him aboard Air Force One so they could personally lobby lawmakers.
To an unusual degree for professional politicians, some senators said afterward that they had not wanted to meet with the mothers and fathers of the dead, or said it was difficult to look at photographs that the parents carried of their young children, now dead.
Sen. Rand Paul, R-Ky., said before Wednesday's vote, "I think that in some cases, the president has used them as props, and that disappoints me."
Without referring to Paul by name, Obama rebutted him firmly. "Do we really think that thousands of families whose lives have been shattered by gun violence don't have a right to weigh in on this issue?" he said.
At the White House, press secretary Jay Carney said some of them had met earlier in the day with lawmakers, who he said should "consider who they're representing.
"Ninety percent of the American people support expanded background checks," he said.
The NRA told lawmakers it intended to keep track of how the votes were cast, and consider them in making decisions about its efforts in the midterm elections for Congress next year.
An opposing group, Mayors Against Illegal Guns, funded by New York City Mayor Michael Bloomberg, said it would do likewise.
The NRA has a long track record in electoral politics, and is viewed by lawmakers in both political parties as unusually effective. Bloomberg's organization has yet to be tested.