Sen. Marco Rubio, R-Fla., spoke pessimistically Thursday about preventing mass shootings like the one that took place in his home state a day earlier.

"I'm trying to be clear and honest here, if someone's decided I'm going to commit this crime, they will find a way to get the gun to do it," Rubio said in a Senate floor speech. "That doesn't mean you shouldn't have a law to make it harder; it just means understand, to be honest, it isn't going to stop this from happening."

Rubio added his comment should not be taken as "because it won't work, I don't even want to hear" others' opinions on legislative reforms to gun laws, but that reality is there are loopholes in the system.

"You could pass a law that makes it hard to get this kind of gun in a new condition," Rubio said. "You're gonna struggle to keep it out of the hands of someone who's decided that that's what they want to use because there's so many out there already, they'd be grandfathered in."

"You can do a background check. The truth is, in almost all of the cases I cited, the individual either erroneously passed a background check or would have passed it or did. Again, even if they couldn't pass the background check, then they could go buy them the way MS-13 does and other gangs and other street elements do — the black market," he added.

The Wednesday shooting in Parkland, Fla., prompted many lawmakers, especially Democrats, to call for enhanced gun controls.