Sen. Bernie Sanders (I-VT) called Republicans “political cowards” for their efforts to restrict voting rights and suggested a constitutional amendment might be necessary to protect the franchise.

“Maybe this is personal because I run for office. Sometimes you lose, sometimes you win,” Sanders said, when Rachel Maddow brought the topic up at Friday’s MSNBC Democratic 2016 Forum.”It has never occurred to me as a candidate to figure out a way to deny the vote to people because they might vote against me. People who do that are political cowards. They’re afraid of a fair election.”

He said the push for voting restrictions was a “a real crisis in this country” and said legislation or “maybe a constitutional amendment” was needed to guarentee that everyone 18 years of age is registered to vote.

“What Republican are doing is so un-American, so outrageous. It is literally beyond belief,” Sanders said. “They’re political cowards and if they can’t face a free election, they should get another job.”