Can Libertarian Gary Johnson Be a Factor in 2016?

Donald Trump is almost certain to be the most unpopular presidential nominee of a major party in modern times. Hillary Clinton is running a close second. And voters' historic distaste for Clinton and Trump has sparked a debate about whether a third-party candidate can play spoiler in November, or even pull off a colossal upset.

You would be right to be skeptical. The third-party scenario is a classic quadrennial pipe dream. But this year, the question merits consideration.