This was a week of tragedy and chaos, with the world looking on in horror as a truck-driving terrorist plowed through a crowd celebrating Bastille Day in Nice, killing 84 people and injuring more than 200. The next evening, factions in the Turkish military attempted a coup against President Erdogan. Meanwhile, Donald Trump postponed his Friday announcement of running mate Mike Pence because, according to campaign manager Paul Manafort, Trump "reacted emotionally" to the Nice attack. There were also reports that, as of late Thursday night, Trump was making calls to see if he could reverse his choice of Pence (a man who wrote that "global warming is a myth," smoking "doesn't kill" and apparently doesn't believe in evolution). Uncertain and unsteady times call for steady and clear-eyed leadership -- not emotionally driven, ad hoc improvising and posturing. On the eve of the Republican Convention, we don't need to know whether Tim Tebow will or will not end up speaking to know that Donald Trump is dangerously unfit to lead the country that leads the world.