A CNN poll released this week shows striking evidence of a shift in American attitudes toward mass shootings: Nearly two-thirds of adults now believe that mass shootings can be prevented, the first time since the shooting at Columbine High School in Colorado that a majority of Americans have felt that way.

The survey suggests the Parkland, Fla., shooting is changing the public attitudes about gun violence in a way that other recent killings haven’t.

As recently as the summer of 2015, when nine black parishioners were shot to death by a white supremacist in a Charleston church, fewer than 40 percent of Americans said that government or society could do anything to stop the shootings.

Just four months ago, when 58 people were killed in a shooting in Las Vegas, a plurality of respondents told pollsters that government and society were essentially powerless to stop these shootings.

Today, however, 64 percent of Americans say that “government and society can take action that will be effective in preventing shootings like the one in Parkland from happening again.” Thirty-two percent say shootings like Parkland “will happen again regardless of what action is taken by government and society.”

The numbers reflect the contours of a familiar political routine: a national tragedy, followed by outrage, prayer and calls for action. Ultimately, however, federal firearm policy remains unchanged, an outcome driven in large part by congressional Republicans’ vehement opposition to substantive regulations on gun ownership. In the past, some red-state Democratic senators, such as North Dakota’s Heidi Heitkamp and West Virginia’s Joe Manchin, have also been instrumental in voting down new gun ­control policies.

The recent shift in the public’s attitudes, however, is primarily concentrated among Republicans. In October, following the Las Vegas shooting, 24 percent of Republicans said that “government and society can take action that will be effective in preventing shootings.”

This month, following the school shooting in Parkland, in which 17 students and educators were killed and 14 more were injured, Republicans’ belief that government and society can stop mass shootings jumped by nearly 30 percentage points, to 52 percent.

The CNN poll shows strong GOP support for at least two specific gun control proposals. Ninety percent said they support a prohibition on gun purchases by felons or people with certain mental health problems. The question, however, didn’t define what mental health problems would qualify for this policy.

More than 60 percent of Republicans also support raising the age limit to 21 for all gun purchases, including rifles. Currently, federal law sets an age limit of 21 for handgun purchases from licensed dealers and a limit of 18 for rifles. Because of that, the Florida school shooter had been able to legally obtain the military-style rifle used in the shooting despite being only 19.

Nearly half of Republicans favor a ban on magazines capable of holding more than 10 rounds. Over one third support a ban on all semi-automatic rifles, a measure that would be more restrictive than the 1994 assault weapons ban, which only outlawed certain types of semi-automatic rifles. A limit on the number of guns individuals could own is even less popular among GOP ­voters.