Story highlights US troops have an obligation not to follow illegal orders

Trump's campaign statements indicate he might seek the use of waterboarding

Washington (CNN) When Donald Trump takes office, his plate will be full with national security challenges ranging ISIS to Russia. But first up may be the issue of how top military officers deal with the new commander in chief himself.

There is civilian control of the military, and there is unquestioned loyalty to any president. But Trump comes into office with a series of campaign promises that include the possibility of ordering illegal action by the US military.

The issue getting perhaps the most attention is Trump's campaign statements he might institute waterboarding of terrorism suspects. Waterboarding is considered torture, which is illegal under US and international law. Other Trump campaign promises that worry some commanders and troops include the notion of bombing with little regard for civilian casualties or taking Iraq's oil supplies, also potential violations of international law.

Pentagon Press Secretary Peter Cook noted on Thursday that all US troops have an obligation not to follow illegal orders. And he made clear the decades of expectations by troops and commanders that they wouldn't be asked to do so.

"I don't think this is something we should even be discussing," Cook said in response to a question from CNN. "They're not going to get an order in violation of the law."

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