There have been more mass shootings in the United States than any other country in the world in the post World War II era.

With the spate of mass killings rising in recent decades, the pressure on politicians to act has increased. 75% of Americans say gun control is a very or somewhat important issue to them, according to a recent YouGov poll.

The roughly two dozen Democratic presidential candidates have released a number of plans to address the number of deaths caused by guns.

Democratic frontrunner, former Vice President Joe Biden, authored the 1994 bill which banned the manufacture of assault weapons. A study published in January found “mass shooting fatalities were 70% less likely to occur during the federal ban period.” The bill had a sunset clause and expired in 2004.

Biden’s campaign reiterated his support for re-enacting the assault weapons ban legislation, which includes a prohibition on high-capacity magazines. During the June presidential debate, Biden expressed support for “smart guns,” or firearms unable to shoot unless a biometric scanner matches the finger on the trigger to prints registered to it.

Sen. Bernie Sanders, I-Vt., has called for an expansion of background checks, the ending of the “gun show loophole,” and a high-capacity magazine and assault weapons ban.

Sanders voted for the assault weapons ban in 1994 as a member of the U.S. House of Representatives, and co-sponsored a bill which would implement a federal “red flag law” in February. Red flag laws allow for court orders for the removal of firearms from a person who may be a danger to themselves or others.

“Gun violence is a national health emergency in this country,” Sen. Elizabeth Warren, D-Mass., said in the June presidential debate. “We need to treat it like that. We can do the things that are sensible.” 

Warren as a senator voted to ban high-capacity magazines capable of holding more than 10 rounds of ammunition and voiced support for universal background checks and banning “weapons of war.” 

Sen. Kamala Harris, D-Calif., has proposed using executive action to implement background checks for gun sales by anyone selling more than five guns per year. Harris said she would undertake that action if Congress did not pass gun control legislation in the first 100 days of her presidency, if elected.

Harris joins Biden, Sanders and Warren in supporting an assault weapons ban, and a ban on high-capacity magazines. Mayor Pete Buttigieg, D-South Bend, joins his Democratic rivals in calling for those gun control measures, as does Sen. Amy Klobuchar, D-Minn.

Former Rep. Beto O’Rourke, D-Texas, who represented the El Paso area in Congress for six years, left the campaign trail in the wake of Saturday’s shooting, which left at least 20 people dead. O’Rourke was in Nevada when news of the shooting broke, and before leaving the forum he was at to return home he called for “universal background checks” and “a stop to all sales of weapons of wars.”

During his time in Congress, O’Rourke co-sponsored a bill requiring background checks for gun show sales.

Fellow Texan and presidential candidate, former Housing and Urban Development Sec. Julián Castro said in the aftermath of Saturday’s attack “the answer is to make sure those guns never get in the hands of people like [the alleged shooter] in the first place,” Castro said.

Castro supports gun buyback programs, in addition to an assault weapons ban and universal background checks.

Rep. Tim Ryan D-Ohio, announced he is suspending his presidential campaign to return to his home state, where another shooting took place early Sunday. 

“We have to put pressure on [Senate Majority Leader] Mitch McConnell to start the background check bill,” Ryan said. “We need an assault weapons ban; we need to study this is as a public health crisis as it is.”

Businessman Andrew Yang’s campaign website calls for a “common sense licensing policy” for firearms, and an increase in the availability of mental health resources.

Sen. Cory Booker, D-N.J., is also calling for a gun licensing program, but otherwise his plan is similar to that of the frontrunners.

The AP reports two gun-control advocacy groups will invite presidential candidates to a forum on gun control in Las Vegas on the second anniversary of the deadliest mass shooting in modern U.S. history that took place there Oct. 2, 2017.