Story highlights President Barack Obama is defending Hillary Clinton over email server questions

He's taking a largely legalistic approach

Washington (CNN) As President Barack Obama works to keep a Democrat in the White House, his public assessments of Hillary Clinton remain constrained politically and legally, a scenario that's unlikely to change anytime soon.

Much of Obama's acclaim for the Democratic presidential front-runner remains couched in generic terms about her tenure as his top diplomat, broad enough to offer praise while not alienating the significant number of young people who are voting for her rival. And his replies to questions about her use of a personal email server while serving as his secretary of state remain carefully crafted as his administration investigates the set-up.

It's never been a secret that most of Obama's closest allies regard Clinton as the more obvious caretaker of his legacy, much of which has been built through executive action and therefore will rely on his Oval Office replacement to maintain.

But the President himself has taken pains in the last year to suppress any public leanings in the Democratic nomination contest, meeting privately with both Clinton and rival Vermont Sen. Bernie Sanders while maintaining official neutrality on the race.

He did vote in the Illinois primary -- meaning he plainly prefers one candidate over the other -- and hasn't been hesitant about defending his former secretary of state against political attacks and allegations of wrongdoing. But in doing so, his hands remain tied.

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