One reason 60 million voters elected Donald Trump is because he promised to change Washington’s culture of self-dealing, and if he wants to succeed he’s going to have to make a sacrifice and lead by example. Mr. Trump has so far indicated that he will keep his business empire but turn over management to his children, and therein lies political danger.

Mr. Trump has for decades run the Trump Organization and during the campaign said if he won the Presidency he’d turn over the keys to Donald Jr., Eric and Ivanka, all of whom...