O'Malley interrupted moderators in the Democratic debate to get a word in on gun control.

He says the lack of progress on gun safety is due to the "flip-flopping political approach in Washington" represented by Clinton and Vermont Sen. Sanders.

O'Malley points to his record of pushing gun safety laws as governor of Maryland. O'Malley says he overcame objections from the National Rifle Association and crowds that protested new gun safety laws.

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The heated remarks from O'Malley prompted pushback from Clinton and Sanders.

Sanders said: "Let's calm down a little bit, Martin."

Clinton said: "Let's tell the truth, Martin."