
Democratic presidential candidates take the stage before debating in Las Vegas on Tuesday, October 13. From left are former U.S. Sen. Jim Webb, U.S. Sen. Bernie Sanders, former Secretary of State Hillary Clinton, former Maryland Gov. Martin O'Malley and former Rhode Island Gov. Lincoln Chafee.

An audience member watches the debate, which was the first Democratic debate of this election cycle.

Sanders speaks during the debate. CNN's Mark Preston said Sanders' opening remarks "hit on all of the hot-button liberal issues: Take back the government from billionaires, climate change. He all but said it is time for a revolution."

Clinton is the national front-runner in the Democratic race. "I would not ask anyone to vote for me based on my last name," she said during the debate. "I'm campaigning because I think I have the right combination of what Americans are looking for ... and I can take the fight to Republicans."

Webb listens to moderator Anderson Cooper during the debate. Webb is a former Marine who also served as secretary of the U.S. Navy. "You may be sure that in a Webb administration, the highest priority will be the working people who every day go out and make this country stronger at home, and who give us the right reputation and security overseas under a common-sense foreign policy," Webb said.

O'Malley faces the camera while delivering remarks. He went after Sanders on gun control early in the debate, and -- in what could be interpreted as a veiled swipe at Clinton -- he said, "I am very clear about my principles."

Chafee touted his experience, saying he is the only candidate who has been a mayor, senator and governor. "I have had no scandals. I've always been honest. I have the courage to take the long-term view, and I've shown good judgment," he said in his opening statement.

One of the debate's memorable moments was when Sanders and Clinton shook hands following Sanders' take on the Clinton email scandal. "Let me say something that may not be great politics, but the secretary is right -- and that is that the American people are sick and tired of hearing about the damn emails," Sanders said. "Enough of the emails, let's talk about the real issues facing the United States of America."

Audience members watch the debate.

The Democratic field this year is less than half the size of the Republican field.