WAUKEE (Iowa) • US President Barack Obama has praised Democratic presidential candidate Hillary Clinton's political experience, giving her campaign a boost as she battles an insurgent rival, Vermont senator Bernie Sanders, a week before the Democratic presidential nominating process kicks off.

Mr Obama's kind words for his former secretary of state, in a Politico interview published on Monday, will help Mrs Clinton as she tries to link her campaign more closely with the President and so draw in more support from his backers.

While never criticising Mr Sanders, whose campaign is focused on pledges to redress social inequality and contain Wall Street excesses, Mr Obama praised Mrs Clinton's experience and suggested that her messages are grounded in realism.

"She's extraordinarily experienced - and, you know, wicked smart and knows every policy inside and out - sometimes (that) could make her more cautious, and her campaign more prose than poetry," he said.

All three Democrats in the race - the other being former Maryland governor Martin O'Malley - were given prime time on Monday night in a nationally televised town hall meeting at Drake University. It featured separate appearances by the candidates.

Mrs Clinton faced the challenge of convincing Democrats not to be swayed by Mr Sanders' populist rhetoric and to stick with her despite a clamour for candidates outside the political establishment.

Mr Sanders argued that his own judgment, not Mrs Clinton's experience, is the most crucial quality. But Mrs Clinton, in response, evoked Mr Obama, saying that when he selected her to be secretary of state, he gave approval to her judgment. "You have to have somebody who is a proven, proven fighter," she said.

Mr O'Malley, who trails his rivals by significant margins, urged his supporters to "hold strong". "We cannot be this fed up with our gridlocked, dysfunctional national politics and think that a resort to old ideologies or old names is going to move us forward," he said.

Mrs Clinton has argued that Mr Sanders lacks experience to tackle a wide range of issues. "When you're in the White House, you cannot pick the issues you want to work on," she told the Jewish Federation of Greater Des Moines on Monday.

In an echo of that, Mr Obama said to Politico: "One thing everybody understands is that this job right here, you don't have the luxury of just focusing on one thing... I think what Hillary presents is a recognition that translating values into governance and delivering the goods is ultimately the job of politics."

REUTERS, AGENCE FRANCE-PRESSE