It didn’t take long for things to get tense at Tuesday night’s Democratic debate.

Front-runner Hillary Clinton accused Vermont Sen. Bernie Sanders of not being “tough enough” on guns.

“We have to look at the fact that we lose 90 people a day from gun violence,” Clinton said. “It’s time the entire country stood up to the [National Rifle Association].”

Sanders repeatedly pointed out that he holds a D-minus rating from the National Rifle Association, and argued that it was necessary to bridge the cultural divide between urban and rural America when it comes to common-sense gun reform.

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But the self-described Democratic socialist could not escape heated criticism for voting against the Brady Act, which mandated federal background checks on firearm purchases, and supporting a federal bill that would have shielded gun shops from crushing lawsuits. Sanders said that it was “a large and complicated bill,” with some provisions that he liked, and some he didn’t.

“It was pretty straightforward to me,” Clinton countered. She voted against it.

Tuesday’s debate comes less than two weeks after a lone gunman opened fire on a community college campus in Roseburg, Oregon, killing nine people before taking his own life. Shortly after the shooting, President Obama delivered an emotional address that spotlighted the nation’s shortcomings in keeping guns out of dangerous hands.

“Our thoughts and prayers are not enough,” Obama said in a statement from the White House briefing room. “It’s not enough. It does not capture the heartache and grief and anger that we should feel. And it does nothing to prevent this carnage from being inflicted someplace else in America.”