In the space of four days, Donald Trump has plunged his presidential campaign into a crisis. He has done this by igniting controversies, each of which was entirely avoidable and which, taken together, have turned his campaign for the presidency into a tire fire.

• He relitigated disputes over his depictions of a disabled New York Times journalist and a Fox News achor, Megyn Kelly.
• He blundered into a Democratic trap by lashing out in response to a goading convention speech by a Muslim father whose son, an American soldier, died heroically fighting in Iraq.
• He doubled down on this spat by casting aspersions on the soldier’s bereaved Muslim mother, and thus created a four-day media firestorm out of an unseemly incident that could have been dismissed quickly with a deft and honorable response. Does Trump really think voters want a president who can be goaded so easily into overreaction?
• And he refused to endorse Rep. Paul Ryan, pointedly echoing the half-hearted words used by the speaker about him two months ago. In doing so, Trump perfectly encapsulated the deepening suspicion that he his incapable or unwilling to do what is politically advisable instead of lashing out at anyone who has shown him less respect than he thinks is his due.

You can tell that Trump and his despondant campaign team know where this is heading because the candidate is already making excuses for defeat, alleging that the November election will be “rigged.”