Democrat debate: Candidates name their enemies
During the debate, host Anderson Cooper introduced a quote from former President Franklin D Roosevelt - "I ask you to judge me by the enemies I have made" - and asked the five candidates which enemies they were most proud to have made. The BBC examines their responses.
Hillary Clinton: Gun lobby, big pharma... and Iran
"Well, in addition to the NRA, the health insurance companies, the drug companies, the Iranians... Probably the Republicans."
Clinton has defended the deal over Iran's nuclear programme - but in a speech in September insisted the deal was not a step towards normalising relations with the Islamic Republic and said that, if elected president, she would not hesitate to take military action against the country if it attempted to develop nuclear weapons. She stressed the US commitment to Israel and accused Iran of having "American blood on its hands".
Bernie Sanders: Wall Street and big pharma
"As someone who has taken on probably every special interest that there is in Washington, I would lump Wall Street and the pharmaceutical industry at the top of my life of people who do not like me."
Sanders has called for wide-reaching financial reforms and supports breaking up financial institutions that some deem "too big to fail" as well as reintroducing controls under the 1933 Glass-Steagall Act, designed to curb banking excesses, that was repealed in 1999 under pressure from Wall Street bankers, who argued they needed more freedom to face foreign competition, especially from London.
Sanders also campaigns for lower prescription charges, claiming that 35m Americans aged between 19 and 64 cannot afford to pay the current rates and accusing pharmaceutical companies of putting profits ahead of patients.
Lincoln Chafee: Big Coal does not dig me
"I guess the coal lobby. I've worked hard for climate change and I want to work with the coal lobby. But in my time in the Senate, I tried to bring them to the table so that we could address carbon dioxide. I'm proud to be at odds with the coal lobby."
Chafee - formerly a Republican who left the party and became first an independent candidate and then a Democrat - voted against allowing drilling in the Arctic National Wildlife Refuge and was a member of the Republicans for Environmental Protection. He has been endorsed by environmental organisations the Sierra Club and the League of Conservation Voters.
Martin O'Malley: The gun lobby. Period.
"The National Rifle Association."
During his second term as Maryland governor, O'Malley introduced tough gun control legislation, including provision that no one could buy a handgun without first passing a training course and providing fingerprints to a police database.
Jim Webb: My enemies aren't around anymore...
"I'd have to say the enemy soldier that threw the grenade that wounded me, but he's not around right now to talk to."
Webb received the Navy Cross for "extraordinary heroism" during the Vietnam War, when he simultaneously pushed a colleague away from a grenade thrown by an enemy soldier from a bunker, fired his weapon and used his body to shield his colleague from the grenade blast, sustaining shrapnel wounds, before destroying the bunker with one of his own grenades.