There's rarely much to be gained from supporting a third-party candidate for President. Despite his recent efforts to shed the appellation "spoiler," Ralph Nader did cost Al Gore the 1980 election. Ross Perot, in contrast, aided Bill Clinton's victory by drawing more from the Republican side. Neither ever had a realistic chance of winning on his own.
But now we are presented with Gary Johnson, former governor of New Mexico, who has outdone some other egregious candidates in his gaffes regarding basic foreign policy familiarity. You don't have to be a policy maven or wonk to be able to respond to simple questions about international leaders and the situation in Aleppo. Not to know what either is strikes me as ludicrous in a serious candidate.
This lacklustre performance merely emphasizes the danger in supporting candidates who only can play that spoiler role. Yes, at least one of our major-party candidates is a disaster, but that does not excuse assuming a righteous, above-it-all attitude justifying voting for someone who has no chance except to possibly flip the election result.
I suppose where I'm going is to say that a protest vote is fine if it really doesn't make a difference, but it made a difference in 2000, especially with a Supreme Court jumping into politics with a ruling that defiantly proclaimed it was not a precedent. It could well make a difference in certain key states this time. This is no year to throw away your vote.