Republican presidential candidate Sen. Marco RubioMarco Antonio RubioRubio: Kaepernick deserves to be in the NFL Congress — when considering women’s health, don’t forget about lung cancer Anti-Maduro Venezuelans not unlike anti-Castro Cubans of yore MORE (Fla.) ripped President Obama's new gun control measures Tuesday, calling him "obsessed" with the issue.

"It undermines the Second Amendment, and it will do nothing to keep people safe," Rubio told Fox News's Bill Hemmer during an interview aired on "America's Newsroom."

"Barack ObamaBarack Hussein ObamaHolder: DOJ, FBI should reject Trump's requests The Hill's 12:30 Report — Sponsored by Delta Air Lines — Frenzy over Kennedy retirement rumors | Trump challenges DOJ Asian American and Pacific Islander community will be critical to ensuring successful 2018 elections for Democrats MORE is obsessed with undermining the Second Amendment — an important protection our Constitution recognizes and defends for us, and he's looking for any way possible to undermine it. He's been doing this forever," Rubio said. 

Republicans have panned Obama's move to expand background checks for people buying firearms online or at gun shows, and at least one lawmaker has floated withholding funding from the Department of Justice to stop him.

Obama's executive action comes just a week before his final State of the Union address. By tackling background checks head on, he is keeping the spotlight on the gun issue just weeks before the first ballots are cast in the presidential race to succeed him.

"This president is obsessed with undermining the Constitution in general, but the Second Amendment in particular. He is obsessed with undermining it, and it will do nothing," Rubio said Tuesday.