What the numbers show on Americans' opinions of gun control measures

Gun control measures are once again being debated after one of the worst school mass shootings ever has shattered a Texas community.

Nineteen children and two teachers were killed Tuesday when a gunman opened fire at an elementary school in Uvalde. The suspect had legally purchased two AR-15-style rifles in the days following his 18th birthday, authorities said.

Gun laws vary widely by state, with Texas home to some of the weakest in the country, according to the Giffords Law Center to Prevent Gun Violence. Republican lawmakers in the state have repeatedly loosened gun restrictions even after recent mass shootings there.

In the wake of the Uvalde shooting, several members of Congress have said they will look at gun control legislation when they return from their recess next week -- including potential measures that show wide support among Americans.

"Knowing we can't turn back the clock to prevent this tragedy from occurring, the obvious question then is how do we prevent something like this from happening," Sen. John Cornyn, R-Texas, said on the Senate floor Thursday. "I'm eager to see whether there are any gaps that might have done something to make this attack less likely, that might have actually even prevented this attack from taking place."

Sen. Mitt Romney, R-Utah, told reporters Wednesday that he's open to supporting certain gun control measures -- including expanded background checks.

"Improving our background check capability makes sense," Romney said.

House Majority Leader Steny Hoyer, D-Maryland, said Wednesday that the House next month will move on a bill to create a national "red flag" law. The proposed bill would allow family members or law enforcement officers to "petition for an extreme risk protection order with respect to an individual who poses a risk to themselves or others."

Universal background checks and red flag laws are widely supported by the public. An ABC News/Washington Post poll conducted in September 2019 found 89% support for universal background checks and 86% support for red flag laws.

There was broad bipartisan support, as well; mandatory background checks and red flag laws won support from at least eight in 10 Republicans and conservatives, and as many or more of all others, the poll found.

An April 2021 Quinnipiac University poll on gun laws similarly found overwhelming support for requiring background checks for all gun buyers (89%). Support was similarly high among Republicans (84%).

There was less broad support for other gun control measures. The 2019 ABC News/Washington Post poll found that six in 10 support banning high-capacity ammunition clips and 56% support banning the sale of assault weapons. Support for an assault weapons ban varied greatly along political lines, with 81% of Democrats, 55% of independents and 33% of Republicans in favor.

Additionally, the poll found that 52% support a mandatory buyback program in which the government would require owners to turn in their assault weapons in exchange for payment.

The 2021 Quinnipiac University poll was similarly divided on other gun control measures, with 52% support for a nationwide ban on the sale of assault weapons and 51% support for a nationwide ban on sale of high-capacity ammunition magazines that hold more than 10 bullets.

In the Uvalde massacre, the gunman had a total of seven 30-round magazines with him in the classroom where the shooting took place, multiple law enforcement sources told ABC News.

One 30-round magazine was in an AR-15-style rifle used in the shooting and six magazines were carried on a tactical vest worn by the shooter, with the potential to hold 210 rounds.

It is unclear how many rounds were expended.

In the massacre's aftermath, Senate Majority Leader Chuck Schumer said the Senate would be voting on gun control measures, though it's unclear on what policies exactly.

"Let me be clear -- we are going to vote on gun legislation," he said on the Senate floor Wednesday. "The American people are tired of moments of silence, tired of the kind words offering thoughts and prayers."

ABC News' Lalee Ibssa and Trish Turner contributed to this report.