(SOUNDBITE) (English) U.S. PRESIDENT DONALD TRUMP, SAYING: "And we believe in freedom and liberty and the right to keep and bear arms." President Donald Trump on Friday vowed to protect gun rights as the 2020 presidential race heats up, issuing a familiar warning at the National Rifle Association's annual meeting in Indianapolis.

(SOUNDBITE) (English) U.S. PRESIDENT DONALD TRUMP, SAYING: "Far left radicals in Congress want to take away your voice, your rights, and they especially want to take away your guns." In previous election cycles, recognizing the NRA's clout, Democrats have sometimes avoided the issue.

But with mass shootings, such as last year's Parkland massacre, on the rise, Democratic candidates such as Kamala Harris and Beto O'Rourke, among others, are so far not shying away from talking gun control.

(SOUNDBITE) (English) FORMER REP.

BETO O'ROURKE, (D) TEXAS, SAYING: "Those states that have adopted universal background checks for every firearm purchase have seen a near 50 percent reduction in gun violence." (SOUNDBITE) (English) SEN.

KAMALA HARRIS, (D) NEW JERSEY, SAYING: "We're not waiting for a tragedy.

We've had the worst of tragedies." Harris has pledged to expand background checks and to use executive actions if Congress does nothing.

Democrats have been emboldened by recent state laws that have dented the NRA's aura of invincibility.

In the wake of Parkland, Florida's Republican then-governor Rick Scott pushed through a law raising the minimum age to buy any firearm from 18 to 21.

This year, in a rare break with the NRA, Trump himself banned the rapid-fire bump stocks used in the 2017 mass shooting in Las Vegas that killed 58 people.

But on the NRA stage Friday, Trump sought to reassure gun owners, announcing he will withdraw the U.S. from a U.N.

Treaty setting rules for the sale of arms on the global market.