As Democrats called Thursday for restricting access to weapons after the worst high school shooting in American history, two South Florida Republicans, Sen. Marco Rubio, who received millions of dollars in political help from the National Rifle Association, and Rep. Mario Diaz-Balart, the single largest recipient of direct NRA campaign cash among Floridians in the House of Representatives since 1998, said gun control legislation won't stop mass shootings.

Rubio's voice trembled with emotion during a 30-minute interview with the Miami Herald in which he argued that legislation to limit access to semi-automatic rifles like the AR-15 or laws to make it tougher to purchase firearms legally wouldn't have prevented the tragedy at Marjory Stoneman Douglas High School in Parkland.

"It is unfair to argue that there's nothing we can do other than be more careful," Rubio said. "It's also unfair to argue that the reason why people are suffering today is because there's some great law out there that if we had just passed it, it wouldn't have happened. It's not accurate. Both of those things are wrong."

Rubio, who earned an A+ rating from the National Rifle Association during his 2016 reelection campaign and who ranks among the top 20 members of Congress in money received — $3.3 million — from gun-rights interest groups in either direct or indirect campaign help, said that Wednesday's shooting touched on multiple areas of public policy, including firearms, mental health funding, school safety and law enforcement oversight. A bill that affects one area of public policy doesn't prevent the next mass shooter from successfully plotting an attack, Rubio said.

"I'm not saying that these can't be balanced out, but these public policy issues are more complex than what is often reported," Rubio said. "There's a rationale beyond just the NRA why some of these things meet resistance."

Arizona Democratic Rep. Ruben Gallego, a former Marine who used a version of the AR-15 when he served in the Iraq War, said Rubio's response to the shooting was no different than anything else he's heard from Republicans.

"When you have people like Marco Rubio, who has had several killings in his state by people using these types of weapons, and he consistently asks for prayers and does nothing, it's symptomatic of what is going on with the Republican Party," Gallego said. "Marco Rubio and the Republican Party are in the pockets of the NRA and they'll never do anything. They'll just talk a game and think everyone forgets."

Rubio said groups such as the NRA support him and run crucial television ads during heated campaigns because he supports gun rights.

"I think there's two reasons why they would do it," Rubio said. "One, they didn't like my opponent, and two, I'm a supporter of the Second Amendment and I remain a supporter of the Second Amendment. The Second Amendment is not the cause of this. The cause of this is individuals who happen to abuse that liberty and that constitutional right for the purposes of conducting these atrocities."

But Rep. Debbie Wasserman Schultz, a Broward County Democrat, said that any legislation dealing with safety, including gun regulations, isn't able to keep bad things from happening. Instead, laws are designed to put obstacles in the path of potential accidents or crimes.

"Would it have been an absolute certainty that [the killer] couldn't have gotten a weapon? No," Wasserman Schultz said. "But if you make it harder for him, you put an obstacle in his path, that's what safety legislation is all about. There are things that we can do that protect the so-called Second Amendment. There are things that I think reasonable people, if willing to sit down, could agree to."

Those "reasonable solutions" for Wasserman Schultz include expanded background checks and limiting the purchase of rifles, such as the AR-15 that was used in Wednesday's shooting, to people who are 21 or older. The shooter purchased an AR-15 after he turned 18, which is legal in Florida.

Diaz-Balart, R-Miami, the single largest recipient of direct NRA campaign cash — $26,450 — among Floridians in the House of Representatives since 1998, said gun control legislation wouldn't stop mass shootings.

"Would gun control stop this? No," Diaz-Balart said. "I want to make sure we look at things that could make a difference."

Rubio agreed with Diaz-Balart's position, and said that Congress already passed a ban on assault rifles in the 1990s (which was later overturned) and that the ban didn't work.

"There are all kinds of guns that are outlawed and weaponry that's outlawed and/or special category," Rubio said on the Senate floor. "The problem is that we did that once, and it didn't work for a lot of reasons. One of them is there is already millions of these on the street. And those things, they last 100 years, and so you could pass a law that makes it hard to get this kind of gun in a new condition. But you're going to struggle to keep it out of the hands of someone who has decided that's what they want to use because there are so many of them out there already that would be grandfathered in."

Diaz-Balart said investing more money in mental health programs is one area where Congress could make a difference, a policy that may breed future agreement between Democrats and Republicans. Wasserman Schultz, for example, said adding mandatory mental health evaluations at public schools, like vision and hearing tests, could go a long way.

But no Republican in the 24 hours after the shooting introduced new legislation to fund mental health programs or reduce access to guns. Miami Republican Rep. Carlos Curbelo, who began a push to ban "bump stocks" after the mass shooting in Las Vegas, where a gunman killed dozens after using a currently legal accessory that allows semi-automatic weapons such as the AR-15 to fire like automatic weapons, said he hopes there's now renewed attention to his effort.

"I think I've been pretty explicit about the lack of political courage on this issue," Curbelo said. "I really thought that banning bump stocks would be a low hurdle that Congress could clear, but they failed to act. There is a very healthy middle ground where we can protect and even enhance Second Amendment rights for law-abiding citizens, while strengthening laws and regulations to keep dangerous weapons out of those whose intention it is to kill and hurt innocent people. There are a lot of younger Republicans who are moving in this direction."

Gallego said aligning rifle laws with handgun laws is one step that should garner widespread support.

"We should align our handgun laws when it comes to our high-powered rifles," Gallego said. "Those type of weapons are the ones that are used in war, it's the type that I used in war. These young kids at 18 are not equipped mentally to deal with or use these weapons responsibly."

He also said Curbelo's stance is "great politics," but that it won't have any substantive impact as long as Republican Speaker Paul Ryan controls the House of Representatives.

And Wasserman Schultz said the simplest way to ensure a long-term solution is for voters to change the complexion of Congress in the 2018 elections.

"When 30 children were killed, nothing happened. When a colleague of ours was shot in the head, nothing happened. When a colleague of ours was shot on the baseball field, nothing happened," Wasserman Schultz said. "So elections are part of the key to this and election results are part of the key to solving this problem."