Obama is expected to announce action on gun control early this week, and he will meet with CNN's Anderson Cooper on Thursday for a one-hour town hall about the issue at George Mason University.
However, not everyone is happy about the president's promise for increased gun control — including the Florida senator.
"[Obama] has waged war on the Constitution," Rubio told a crowd on Sunday in Raymond, N.H. "He is obsessed with gun control." The senator added that he believes Obama "meant to further erode the Second Amendment."
"Law-abiding gun owners are not the problem in this country," he continued. "The problem are criminals, and criminals don't care what laws you pass. You can pass all the gun laws in the world that you want. It will not stop the criminals."
Rubio said that the shooters in San Bernardino, Calif., would have passed the background checks Obama will likely push. He previously argued that stricter gun control laws wouldn't have prevented the October mass shooting at Umpqua Community College in Oregon.
His anti-gun control message played well with the Republican voters of New Hampshire, many of whom have a deep commitment to gun rights.
"Don't worry," Rubio told the crowd. "On my first day in office, behind that desk... those orders are gone."