The Paris attacks opened a discussion about how the United States should combat the threat from Islamist militants.
Clinton said "this cannot be an American fight, although American leadership is essential". O'Malley, a former Governor of Maryland and Baltimore Mayor, replied: "This actually is America's fight. It cannot solely be America's fight." Sanders challenged Clinton by linking the rise of Isis (Islamic State) to the war in Iraq and criticising her for her vote to authorise the invasion when she was a senator from New York.
O'Malley and Sanders, a US senator from Vermont, raised questions about the breadth of the turmoil in the Middle East and whether US policy was equipped to deal with it. "As Americans, we have shown ourselves to have the greatest military on the face of the planet, but we are not so very good at anticipating threats and appreciating just how difficult it is to build up stable democracies," O'Malley said.
Clinton tried to showcase the experience she gained during four years as Secretary of State, stressing repeatedly the complicated nature of global issues, speaking in detail about the roles of specific countries, such as Turkey and Jordan. "I don't think you can paint with a broad brush." "Many of the fights that are going on are not ones that the United States has either started or has a role in."
The debate then shifted to issues that included immigration, healthcare, the minimum wage and gun control, with Sanders calling for broad tax reform that eliminates corporate loopholes and questioning why Wall Street has been a major Clinton campaign contributor, while O'Malley criticised Clinton's plan to deal with Wall Street and the big banks.
Clinton sought to assert leadership on the issue of gun control, accusing Sanders of not doing enough in the Senate to toughen gun regulations and crack down on the firearms industry.