As students walked out of thousands of schools Wednesday to memorialize victims of school shootings and demand action, new polling finds Americans expressing more support for gun restrictions than at any point in more than two decades.

A Gallup poll released Wednesday found that 67 percent of adults say laws covering the sale of firearms should be “more strict,” up seven points since October and up 20 points since 2014. No Gallup poll has shown higher support for increasing restrictions since 1993, when two-thirds of the public supported stricter laws just after Congress passed the Brady Handgun Violence Protection Act, which mandated background checks for gun purchases from licensed dealers.

The Gallup survey also found that the percentage of Americans who said that “guns” or “gun control” was the nation's most important problem jumped from 1 percent in January to 13 percent this month, vaulting to a record high in monthly surveys tracking the issue since 1994. Guns trailed only “dissatisfaction with government” at 22 percent, and topped immigration (9 percent) and race relations (7 percent) as the nation's most important problem.

The Gallup survey echoes three other polls showing an increase in support for gun restrictions a month after a mass shooting left 17 teenagers and educators dead at Marjory Stoneman Douglas High School in Parkland, Fla.

  • A CBS News poll found an eight-point rise in the percentage of adults saying “gun control laws should be more strict” since December, 57 percent to 65 percent.
  • A CNN-SSRS poll found an 18-point spike in the percentage of adults favoring “stricter gun control laws” since October, 52 percent to 70 percent.
  • A Quinnipiac poll found a seven-point increase in the share of registered voters supporting “stricter gun laws in the U.S.,” from 59 percent in December to 66 percent one week after the shooting, though this dipped back to 63 percent in a second post-shooting poll released last week.

In its polling about support for gun restrictions over the years, Gallup has found that support peaked at 78 percent in 1990 and stood above 60 percent up through 2000 before dropping into the 50 percent range for most of the George W. Bush administration and falling below 50 percent during most of the Barack Obama years. Support rebounded to 55 percent in 2015 and 2016 and hit 60 percent in the fall, the most recent survey before last month's mass shooting in Florida.

Two critical questions going forward are whether the rise in support for restrictions will last longer than it did after previous high-profile shootings and whether opposition to gun restrictions has now become a significant political risk.

After the 2012 shooting at Sandy Hook Elementary School in Newtown, Conn., that left 26 students and teachers dead, some polls also found a sharp increase in support for gun restrictions. But that support waned in the following months as the Senate failed to pass a proposal requiring background checks for private firearm sales that was supported by most Democrats and opposed by most Republicans. By the 2014 midterm elections, a CNN poll found that “gun policy” ranked ninth out of 11 issues voters said were extremely important in their vote, and Republicans made major gains.

This year, the shift in attitudes appears more consistent across polls, and it comes on top of a steady growth in support for stricter gun laws. Following Sandy Hook, support for stricter gun laws did not reach higher than 58 percent in any of the four polls listed above, but after Parkland the same polling firms show support ranging from 63 percent to 70 percent, a fairly narrow band given differences in the wording of the questions.

Recent polls also consistently show Democrats are more united than Republicans on the issue. Between 85 percent and 93 percent of Democrats support more gun restrictions, but fewer than 60 percent of Republicans are opposed or say laws should be kept as they are or loosened. Rather, the polls show that between 39 percent and 49 percent of Republicans favor stricter gun laws.

On the question of political pressure, a Post-ABC poll immediately after last month's shooting found clear majorities saying that President Trump and Congress are “not doing enough” to prevent mass shootings. And there are signs that Democrats have become more willing to make gun laws a litmus test for candidates in the immediate aftermath of Parkland.

From 2004 to 2013, 30 percent or fewer Democratic, Republican or independent registered voters said they could not support a political candidate they disagreed with on “gun control,” according to Washington Post-ABC News polls. But a Quinnipiac University poll asking a similar question in February found nearly half of Democratic registered voters, 47 percent, saying they could not vote for a candidate they disagreed with on “gun laws.” That was more than double the 21 percent of Republicans who said a candidate's gun position was decisive in their support.

Overall, the shifts in opinion appear to be a reaction to the student-led push for greater gun control after last month's shootings, but it's still too soon to tell how much they will persist after public and media attention fall off.

It is also unclear whether these events will alter the long-running disparity in activism between people on different sides of the gun issue. A Pew Research Center survey last year found 21 percent of gun owners had contacted a public official to express an opinion on gun policy, compared with 12 percent of non-gun owners. And while 15 percent of Americans who support stricter gun laws say they've contacted a public official to voice their opinion on the issue, that rose to 22 percent among those who say laws should be “less strict.”

Emily Guskin contributed to this report.