Jimmy Carter did it. Ronald Reagan did it. George H.W. Bush did it. Bill Clinton did it. George W. Bush did it. And Mitt Romney would have done it.
For the past 40 years, every president and presidential candidate who has had anything other than the most vanilla of investment portfolios - Barack Obama, who had most of his money in Treasury bonds, fell into that category - has put or has promised to put their assets into a blind trust to prevent any kind of conflict of interest between what's good for the country and what's good for their retirement. This wasn't required by law, but it did seem like it was required by good governance.
Donald Trump, though, has refused to entertain this even though he has a much more extensive and eclectic array of holdings, which includes golf courses in the United Arab Emirates, skyscrapers in Turkey and condos in the Philippines. He has said his three adult children will run his business instead.
To be clear - because Trump was asked this in a debate - this would not be a blind trust. To count as one, the Congressional Research Service says, he'd need to transfer "control and management of private assets to an independent trustee who may not communicate information about the identity of the holdings in the trust" to him. In other words, let someone he doesn't know sell all his old assets and buy new ones for him without telling him what they are. Having his kids manage his properties fails both of these tests, especially when they're a part of his transition team. How do we know that they won't staff the Trump administration based on who'd be friendliest to the Trump Organization? Or that they won't hint that the Trump Organization is just an extension of the Trump administration when they're, say, trying to negotiate a real estate deal overseas? We don't. And we can't as long as there isn't any actual separation between Trump's political operation and his business one.
Alan Garten, the Trump Organization's general counsel, has offered a defense of what in modern times are these unprecedented conflicts of interest: that they're plenty precedented in other countries. "It's not unusual," he told the Wall Street Journal, "for people around the world successful in a business to play a role in government." And he's right. There are a lot of places where this is endemic.