The first Democratic presidential debate of the 2016 election is in the record books. The candidates focused on gun violence, Syria, immigration, marijuana legalization, health care and other issues.
Here's some of the highlights from the AP:
How would they differ from President Obama?
How would their presidencies be different from President Barack Obama's?
Hillary Rodham Clinton says, "Being the first woman president would be quite a change from the presidents we've had up until this point, including President Obama."
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Vermont Sen. Bernie Sanders says he would lead a "political revolution" bringing together millions of people to transfer power from large corporations to the working class.
Former Maryland Gov. Martin O'Malley says he would combat recklessness on Wall Street.
Former Rhode Island governor and senator Lincoln Chafee says he would stop wars in the Middle East and former Virginia Sen. Jim Webb says he would reduce the president's use of executive authority.
Disagreement on Social Security
Former Secretary of State Hillary Clinton is suggesting she disagrees with Sen. Bernie Sanders' plans to expand Social Security.
She says she "fully" supports Social Security and "the most important fight we're going to have is defending it against continuing Republican effort to privatize it."
Clinton's comments at the Democratic debate came in response to a question about some of Sanders' pricier policy proposals, including plans to significantly increase payments to Social Security recipients.
Sanders says the plan would be paid for if top earners were asked to pay more in payroll taxes.
Clinton says she and Sanders "agree on the goals, we just disagree on the means."
She says wants to enhance Social Security benefits for the poorest recipients and "focus on helping those people who need it the most."
Dealing with Edward Snowden
Hillary Rodham Clinton and Martin O'Malley agree that Edward Snowden, who exposed widespread NSA surveillance programs and fled to Russia, could have been protected as a whistleblower but broke the law instead.
"Whistleblowers do not run to Russia," O'Malley, the former Maryland governor, said during the first Democratic debate.
Sen. Bernie Sanders, grateful to Snowden for exposing what happened, says Snowden should get a break for educating the public. But he agrees Snowden should be penalized for breaking the law.
As of January 2014, a CBS News poll showed 61 percent of Americans, including 64 percent of Democrats, thought Snowden should have to stand trial rather than be granted amnesty.
Lincoln Chafee isn't one of them. The candidate says he should be brought home. Jim Webb is leaving it up to the legal system.
Bernie Sanders says "black lives matter"
The Vermont senator addressed the nation's racial challenges during the first Democratic presidential debate. He faced criticism from African-American activists earlier in the year for his response to the "black lives matter" movement.
He was asked Tuesday night whether "all lives matter" or "black lives matter." He responded, "Black lives matter."
Sanders says the nation must combat "institutional racism from top to bottom." He's also calling for major reforms to the nation's criminal justice system. He says the U.S. has more people in jail than China -- and a disproportionate number of them are minorities.
Sanders comes from one of the whitest states in the nation. He remains relatively unknown among many black voters, who play an important role in Democratic politics.
Enough with the emails
Former Secretary of State Hillary Clinton and Vermont Sen. Bernie Sanders agree: Enough with the emails.
Sanders passed on the chance to pounce on his political rival's Achilles' heel in the Democratic debate Tuesday night. He says he knows it may not be good politics, but "the American people are sick and tired of hearing about your damn emails."
Clinton and the crowd cheered the moment. She turned to Sanders, shook his hand and said, "Thank you, Bernie."
Clinton says the debate over her use of a private email server as secretary of state is being ginned up by Republicans. She says she made a mistake, but the committee investigating the matter is "basically an arm of the Republican National Committee."
She says she'd rather talk about health care, student debt and issues that affect voters.
Clinton on protecting diplomats
Hillary Rodham Clinton says American diplomats know the risks when they take assignments in dangerous regions.
The former secretary of state briefly addressed diplomatic security when asked during the first Democratic presidential debate about the 2012 attack in Benghazi, Libya. Ambassador J. Christopher Stevens and three other Americans were killed in the siege. Republicans have spent years investigating Clinton's role in the attack.
Clinton says, "When we send them forth, there is always the potential for danger and risk."
She also defends U.S. actions in the country before the attack: "We did not put one single American soldier on the ground in Libya."
Clinton's Democratic opponents declined to criticize her position on Benghazi.
Hey, he endorsed me in 2008
Hillary Rodham Clinton had a quick comeback for an attack from Martin O'Malley -- touting his 2008 endorsement of her previous presidential bid.
During the first Democratic presidential debate Tuesday night in Las Vegas, the former Maryland governor criticized the 2002 decision to authorize the war in Iraq, which Clinton voted in favor of, calling it "one of the worst blunders in modern American history." Clinton has more recently called her vote in favor of the war a "mistake."
O'Malley also questioned her support for a no-fly zone in Syria.
Clinton shot back saying she "was very pleased when Gov. O'Malley endorsed me in 2008 and enjoyed his strong support in that campaign," she said.
On gun laws
Gun laws have emerged as an important issue in the Democratic presidential debate. Polls show Democrats are largely united on the subject, even as Americans as a whole are more ambivalent. A CBS News poll conducted in July and August found that 77 percent of Democrats, but just 52 percent of Americans overall, said gun laws should be made stricter.
But Americans are united on one gun policy proposal. A July Pew Research Center poll showed that 85 percent of Americans, including 87 percent of those in gun-owning households, support requiring background checks for private sales at gun shows -- a fact that former Secretary of State Hillary Clinton referred to during the debate.
Democrats are especially unlikely to think that more guns make people safer. In the Pew Research Center poll, 59 percent of Democrats said gun ownership puts people's safety at risk. In comparison, just 36 percent think it protects people's safety.
Syria no-fly zone
Martin O'Malley says Hillary Clinton's preference for a no-fly zone in Syria would be a mistake.
"I think we have to play a long game," the former Maryland governor says of Syria.
O'Malley is also using the opportunity to condemn the vote to go to war in Iraq under "false pretenses," calling it "one of the worst blunders in modern American history." O'Malley says he believes lawmakers were railroaded by polls. He referenced a John Quincy Adams quote that warned against searching the world for monsters to destroy.
Sanders on deploying ground troops
Vermont Sen. Bernie Sanders says the U.S. should deploy ground troops only when the United States or an ally is attacked.
He says he is "not a pacifist," but believes "in my heart war should be the last resort. I am prepared to take this country into war if necessary."
He says he supported U.S. force in 2001 against the Taliban in Afghanistan after the Sept. 11 attacks. He also supported U.S. force in Kosovo under President Bill Clinton to fight against ethnic cleansing.
But Sanders continues to lament Hillary Rodham Clinton's support for the U.S. invasion of Iraq in 2003.
Sanders says, "I heard the same evidence from President Bush" about Iraq, and decided to vote against the invasion.
On Iraq war
Vermont Sen. Bernie Sanders says the U.S. invasion of Iraq is the "worst foreign policy blunder in the history of the country."
Sanders says Iraq is a quagmire and he will make sure the country never gets involved in anything like it again.
Hillary Rodham Clinton voted to invade Iraq when she was in the Senate in 2002. She has since called that vote a mistake.
Clinton says she also withstood repeated criticism for that vote during the 2008 Democratic presidential debates, but President Barack Obama still trusted her enough to name her as secretary of state.
Dealing with Putin
Former Secretary of State Hillary Clinton says she would "take more of a leadership position" and stand up to Russian President Vladimir Putin over Syria.
Asked during the Democratic debate about Russia's increasing involvement in the Syrian civil war, Clinton says she would take a harder line against Putin. She says, "we have to stand up to his bullying" and "make clear" that Russia has to be part of the solution.
Clinton's comments were her first criticism during the debate of her former boss, President Barack Obama.
Clinton also says she would create "safe zones" to try to ease the massive refugee crisis destabilizing the region.
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