Sen. Bernie Sanders, I-Vt., said on Monday that "terrible people" such as the Boston Marathon bomber and felons convicted of sexual assault should be allowed to vote.

At a CNN town hall in New Hampshire, a Harvard junior asked Sanders if he supports voting rights for all convicted felons, including Dzhokhar Tsarnaev, 25, who was sentenced to death for carrying out the 2013 Boston Marathon bombing which killed three people and wounded more than 260. The Democratic presidential candidate said earlier this month that he believes convicted felons should be able to vote even when they are still behind bars.

In response to the question, Sanders reiterated his belief in a "vibrant democracy," voiced concern about policies under Republican governors which he thought could suppress voters, and stood behind his belief that felons should have the right to vote from prison.

"If somebody commits a serious crime, sexual assault, murder, they're going to be punished," he said. "They may be in jail for 10 years, 20 years, 50 years, their whole lives. That's what happens when you commit a serious crime. But I think the right to vote is inherent to our democracy. Yes, even for terrible people.

"Because once you start chipping away and you say, 'well that guy committed a terrible crime, not going to let him vote,' or 'that person did that, not going to let that person vote,' you're running down a slippery slope," Sanders said. "So, I believe that people commit crimes, they pay the price. They get out of jail, I believe they certainly should have the right to vote. But I believe even if they're in jail, they're paying their price to society, but that should not take away their inherent American right to participate in our democracy."

[Related: Pete Buttigieg breaks with Bernie Sanders on allowing felons to vote from prison]

Most states place prohibitions on voting rights for felons while in prison or for life, but Maine and Vermont, Sanders' home state, allow inmates to vote from prison. Democratic governors in New York and Virginia led efforts in recent years to restore voting rights for felons who are not in prison.

Sanders is polling at about 22.5% in national polls, according to RealClearPolitics' polling average, second to Vice President Joe Biden.