Washington - US President Barack Obama is not officially endorsing a Democratic candidate to replace him just yet, but he had some high praise for "wicked smart" Hillary Clinton.With voting about to begin, the outgoing commander-in-chief avoided doing down Clinton's rival for the party nomination, Bernie Sanders, but was effusive about a woman he bested on the path to the White House.Describing Clinton as ready to start in the Oval Office right away, Obama said the former secretary of state had more experience than any other candidate who was not vice president."She's extraordinarily experienced, and, you know, wicked smart and knows every policy inside and out," Obama told Politico in an interview released on Monday."It means that she can govern and she can start here, day one," but, he warned, "sometimes could make her more cautious and her campaign more prose than poetry".Clinton is the prohibitive favorite to win the Democratic nomination, but has long struggled to rally enthusiasm among large crowds or electrify the party base.Eight years ago Obama successfully used that weakness to his advantage, making soaring oratory the centerpiece of his 2008 win.With less than a week to go until Iowa voters have the first say about who the Democratic and Republican nominees should be in 2016, Clinton and party outsider Sanders are in a statistical tie.Commenting on suggestions that Sanders, who has focused heavily on economic issues is not a well-rounded candidate, Obama said he was not going to dish out advise. "Obviously what he's doing is working," said Obama, before adding that as president "you don't have the luxury of just focusing on one thing.""There's no doubt that Bernie has tapped into a running thread in Democratic politics that says: Why are we still constrained by the terms of the debate that were set by Ronald Reagan 30 years ago?""That has an appeal and I understand it," Obama said, adding: "I think that what Hillary presents is a recognition that translating values into governance and delivering the goods is ultimately the job of politics."