Hillary Clinton emerged unscathed Tuesday from the Democratic Party's first presidential debate, giving her renewed momentum as she gears for a showdown with Republicans over the 2012 Benghazi attack. The frontrunner cut a calm and confident figure as she parried jabs by Senator Bernie Sanders of Vermont and three other hopefuls, who challenged her on everything from political U-turns to gun control and military intervention in the Middle East. But the former secretary of state – who took part in more than 20 debates in the 2008 White House race – appeared mostly polished and composed during a two-hour clash in Las Vegas that was heavy on substance. An independent senator from Vermont who has drawn huge crowds on the 2016 campaign trail, Sanders also delivered a spirited performance as he appealed to the party's left wing, urging action on climate change and attacking Wall Street. There were some fiery moments too, with Clinton accusing Sanders – her chief rival – of being soft on gun control. But Clinton received a surprise boost over her use of a private email server as US top diplomat – seen as an Achilles heel – as Sanders and others came to her defense. "Enough of the e-mails! The American people are sick and tired of hearing about your damn e-mails," Sanders fumed. Expert Larry Sabato argued that both Clinton and Sanders emerged as winners. "Clinton went into the debate the frontrunner and she came out exactly the same – probably strengthened in that role," he said. "Sanders went in as the chief challenger and he came out the same – maybe even strengthened." The debate came just a week before Clinton was due to appear before a panel in the House of Representatives investigating the September 11, 2012 attacks in Benghazi, Libya that killed US ambassador Christopher Stevens and three other Americans. Lawmakers on the Republican-led committee have narrowed their focus to Clinton's use of a private email server while she served as the top US diplomat. She is due to testify publicly before the panel for the first time on October 22. Overall, the debate was spared the dramatic clashes of personalities seen in the first two Republican debates, dominated by Donald Trump, who needled the Democratic candidates by Twitter even before they took to the lecterns. The 67-year-old Clinton was keen to inject excitement into her campaign and show she can rally the Democratic base, while Sanders was testing whether his "political revolution" can translate to the national stage. Sanders put forward passionate arguments for reducing income inequality, insisting he was not a part of the "casino capitalist" system. "I believe in a society where all people do well, not just Wall Street billionaires," he said. Eager to reinforce her liberal bona fides, Clinton said "I don't take a back seat to anyone" when it comes to progressive policies. But when Sanders pointed to Nordic countries as an example for America, Clinton put her foot down. "We are not Denmark. I love Denmark. We are the United States of America," she said. Nearly eight years after her primary campaign clashes with Barack Obama, Clinton seemed to display strong command of the issues and kept her rivals at bay. Her rivals parted company with her on some key policy areas. On Syria, where Clinton supports a no-fly zone, Sanders warned greater intervention could lead to boots on the ground. "When you talk about Syria, you're talking about a quagmire in a quagmire," said Sanders. And Lincoln Chafee, one of the three long-shot hopefuls on the stage, blasted Clinton's "poor judgment calls" in voting as senator to authorize the use of force in Iraq – which she has acknowledged was a "mistake." But former Rhode Island governor Chafee, former Maryland governor Martin O'Malley, and ex-Virginia senator Jim Webb all struggled to generate breakout moments in a debate dominated by Clinton and Sanders. For 74-year-old Sanders, a rumpled, self-declared Democratic Socialist, this was the biggest test of his decades-long political career. Clinton used her rival's moderate position on guns – Sanders hails from Vermont, a rural state with few firearm restrictions – to highlight an area where liberals break with Sanders. Asked if Sanders was tough enough on the gun issue, a steely Clinton said "No, not at all." The election is nearly 13 months away, but Americans begin in February the voting process of selecting their party nominees. Clinton still leads nationally, but she trails Sanders by nearly 10 points in New Hampshire and holds only a modest lead in Iowa. Both are key early-voting states in the nomination process, setting momentum for the rest of the primary race. Asked as the debate was winding up how her presidency would differ from Obama's, Clinton offered the quick-fire response. "Well, I think that's pretty obvious. I think being the first woman president would be quite a change," she said.