Gloves come off between Hillary Clinton and Bernie Sanders before the Iowa caucuses

In their final debate before the Iowa caucuses, the gloves came off between Hillary Clinton and Bernie Sanders.

Shouting over each other at times, the Democratic presidential candidates engaged in some of their toughest exchanges of the campaign, underscoring the narrowing race in the first-to-vote states of Iowa and New Hampshire.

Clinton sought an advantage over the Vermont senator on curbing gun violence.