Why Rex Tillerson Has to Untangle Himself From His Business and Investments

Rex Tillerson has been tapped as Trump's secretary of state.

Rivkin is one of the few ethics lawyers who told ABC News that in his opinion ethically, and not just legally, Trump does not need to divest his business holdings or put them in a blind trust as long as he adopts a “reasonable system” to avoid conflicts.

Richard Painter, the chief White House ethics lawyer for former President George W. Bush, said that Tillerson must go further than simply moving his assets into a blind trust -- he must divest them. “Absolutely, he must give up all stock and stock options in Exxon and distance himself from oil company executives,” Painter told ABC News.

“Resolving the stock conflict through a sale is easy, since the ExxonMobil stock is frequently traded,” noted Matthew Sanderson, a Republican lawyer with Caplin & Drysdale.

Rivkin disagreed, telling ABC News that he does not anticipate exceptional ethical or legal problems with Tillerson’s nomination. “I have every expectation this will be handled properly,” Rivkin said, calling it “entirely normal” to take a position as CEO when you have a fiduciary duty to shareholders and pursue a different position as secretary of state. “You can’t blame him for it.”