“I think those that are hypersensitive to this issue are likely not going to be voting for us anyway, and I understand that, because there are voters who believe that any discussion of the Second Amendment is the compromising of the Second Amendment,” said Walt Maddox, a Democratic candidate for governor of Alabama. “But I believe the vast majority of Democrats, independents and Republicans are not fearful of a discussion on this matter, especially if it’s reasonable, measured and common sense-oriented.”

For his own part, Mr. Maddox declares allegiance to the Second Amendment, but he declined to fill out the questionnaire that the N.R.A. sends to candidates. In the N.R.A.’s view, refusing to complete the questionnaire is “often an indication of indifference, if not outright hostility, to gun owners’ and sportsmen’s rights.”

Other Democrats have mounted far more pointed critiques of the group. The Democratic Party in Virginia, a state that retains a conservative streak despite recent Democratic successes, recently issued a statement referring to N.R.A. “blood money” and declaring that Virginians were excited about “kicking out politicians who value National Rifle Association money over the safety of their sons and daughters, mothers and fathers.”

And in Kentucky, a Democratic state representative from an overwhelmingly conservative district stood on the House floor in February to call for new gun control measures, and said he was surrendering his A rating from the N.R.A.

Some Republicans have also calculated that they can now afford to cross the group to some extent. Gov. Rick Scott of Florida, who is running for the Senate this year, recently signed a Republican-backed gun-control package that was almost immediately challenged in a lawsuit by the N.R.A.

The mass shooting in Parkland, which helped prompt the legislation Mr. Scott signed, appears to have been a political turning point even in places like Montana, which has one of the nation’s highest rates of gun ownership and where candidates often talk about their hunting credentials.