By Ginger Gibson and Steve Holland

Clinton, anxious to put down a threat from the democrat socialist, faced the challenge of convincing Democratic voters not to be swayed by Sanders’ populist rhetoric and promises for more government programs.

The CNN town hall, beginning at 9 p.m. EST, will lack the feel of a normal debate. It is to feature separate appearances by Sanders, former Maryland Governor Martin O’Malley and Clinton, in that order. All three will take audience questions at the event, being staged at Drake University.

Clinton, who lost the Democratic primary to Barack Obama in 2008, was for months the clear front-runner to be the party’s nominee this time around, but opinion polls have showed a surge of support for Sanders in recent weeks.

She argues that while Sanders’ goals on issues such as social inequality are laudable, some are unobtainable and he lacks the 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, you’ve got to be ready to take on every issue that comes your way, including those you cannot predict,” Clinton told the Jewish Federation of Greater Des Moines on Monday.

The Clinton campaign presaged an attack line for Clinton by issuing a news release accusing Sanders of flip-flopping on a variety of issues, such as on gun control and whether he would support normalizing U.S. relations with Iran.

Clinton got some much-needed praise from President Obama in a Politico interview published on Monday, a week before Iowans hold the first nominating contest for the November 2016 election next Monday.

While never explicitly criticizing Sanders, a senator from Vermont whose campaign is focused on pledges to redress social inequality and contain Wall Street excesses, Obama praised Clinton’s experience and suggested several times that Clinton’s messages are grounded in realism.

“(S)he’s extraordinarily experienced – and, you know, wicked smart and knows every policy inside and out – (and) sometimes (that) could make her more cautious, and her campaign more prose than poetry,” Obama said. (Editing by Mary Milliken)