As Obama delivered a powerful address in the White House, surrounded by family members of people killed in shootings, his voice rose to a yell as he said the constitutional rights of Americans to bear arms needed to be balanced by the right to worship, gather peacefully and live their lives.
Obama has often said his toughest time in office was grappling with the December 2012 massacre of 20 children and six adults at an elementary school in Newtown, Connecticut.
"Every time I think about those kids, it gets me mad," Obama said, tears rolling down his cheek.
"That changed me, that day," he said, after being introduced by Mark Barden, whose 7-year-old son was killed in the shooting. "My hope earnestly has been that it would change the country."