Twenty-nine percent of Americans said they agreed with the Senate's decision not to pass the proposed measure, said the poll, which was conducted April 22-25, about a week after the Senate's April 17 vote.
In the same survey, respondents were asked if given the opportunity to vote on key issues on the next election day, would they vote for or against a law that would require background checks for gun purchases.
Eighty-three percent said they would vote for, while 17 percent would vote against.
That's down from 91 percent for and 8 percent against in a similar poll question asked Jan. 19-20, Gallup said. It is unclear if that decline in support for background checks is because of a slightly different wording in the poll question, or if the defeat of the measure by the Senate deflated hopes for legislation.
Either way, Gallup said it is clear an overwhelming majority of Americans would have preferred the Senate pass the measure.
Of those who said they were against background check legislation, most -- 40 percent -- cited the violation of the Second Amendment as their reason.
Twenty-three percent said the government needs to enforce gun laws already in place, 20 percent said criminals will manage to find guns even with a law and 19 percent said a law would not work. In smaller numbers, others said guns aren't the problem, people are; people have a right to privacy, and there's too much government involvement.
The Gallup survey was based on telephone interviews of a random sample of 2,049 adults, ages 18 and older, and has a 4 percentage point margin of error.