Democrat presidential debate: President Obama breaks silence on Hillary Clinton email scandal on eve of first clash

Mr Obama’s comments pave way for Ms Clinton’s rivals to attack her judgement on her email habits while Secretary of State

Hillary Clinton hit out at Donald Trump during the third Democrat candidates' TV debate, calling him "Isis' best recruiter" (AP)

It was surely not what Hillary Clinton most hoped to hear as she prepared for one of the riskiest encounters of her campaign to become the Democrats’ candidate for the White House.

As she was mugging up on the best policy and tactics to use against other Democrat contenders – including Senator Bernie Sanders, the self-declared Democratic Socialist senator from Vermont – in their first televised debate on Tuesday night, Ms Clinton was grappling with an intervention by President Barack Obama.

The self-described Democratic Socialist Senator from Vermont, Bernie Sanders is technically an Independent on Capitol Hill but almost always votes with the Democrats (AP)

Breaking his silence on the dispute over her use of a private email server while serving as his diplomat-in-chief, the man she hopes to replace said: “When we’re in these offices, we have to be more sensitive and stay as far away from the line as possible when it comes to how we handle information, how we handle our own personal data,” he told 60 Minutes. “And, you know, she made a mistake. She has acknowledged it.”

Mr Obama’s comments paved the way for Ms Clinton’s rivals to attack her judgement on her email habits while Secretary of State, at a crucial moment for her campaign. From being the clear front-runner among Democrat candidates, she now faces a real challenge from Mr Sanders, who has overtaken her in the polls in New Hampshire and is not far behind in Iowa.

On the stage at The Wynn, on the Las Vegas Strip, Ms Clinton is expected to tread a delicate line. In spite of the headwinds she has faced about the email controversy and hearings into the Benghazi attack of 2012 when the US ambassador in Libya was killed on her watch, the race for the nomination is still Ms Clinton’s to lose. After New Hampshire and Iowa, it is then this state, Nevada, and South Carolina. She has wide leads in both.

Jim Webb is a Vietnam War veteran and former US Senator for Virginia. He has barely campaigned yet he may draw attention in Las Vegas because of views that do not hew to one or other wing of the party (Getty)

She has other advantages, including endorsements from many key figures in the party – the latest was Congressman John Lewis, a hero of the civil rights movement.

Mr Sanders must demonstrate he can widen his appeal beyond the mostly young, liberal, white and highly educated base of supporters he has built with his radically progressive prescriptions, which would include free college tuition, a health care system far closer to Britain’s NHS and a public funding system for American elections.

The three other contenders, Jim Webb, Martin O’Malley and Lincoln Chaffee, will be desperate for any attention.