"The point is Trump’s character. His original comments about Machado
reeked of sexism and racism. His behavior this week has highlighted,
anew, his impulsiveness and lack of discipline. As the Washington Post’s Paul Waldman,
if Trump did somehow make it to the Oval Office, “he’d have to
regularly set aside whatever impulsive reaction he has to a particular
turn of events in favor of a long-term strategy that would be more
beneficial to the country.” Could he do that? The answer is available on
Twitter."
http://www.newyorker.com/news/john-cassidy/the-meaning-of-trumps-early-morning-tweet-storm