WASHINGTON: Donald Trump once owned up to the force driving him in life: ego. "Almost every deal I have ever done has been at least partly for my ego," the billionaire declared in a 1995 New York Times opinion piece titled, "What My Ego Wants, My Ego Gets." What 70-year-old Donald John Trump wants now is the presidency. To understand why, consider the billionaire's ego not just as mere mortals might see it (an outsized allotment of conceit) but also as Trump himself understands it (an extraordinary drive for excitement, glamour and style that produces extraordinary success.) "People need ego," Trump has said. "Whole nations need ego." The race for the White House, then, is guided by the same...