The lineup for President 2016 appears to be set.
Donald Trump, Republican,
Hillary Clinton, Democrat,
Gary Johnson, Libertarian,
Jill Stein, Green.
Stein hasn't officially been nominated by the Green Party, but it is almost a certainty she will be and a certainty she will not win the Presidential election, but she could have an impact on the election results.
It's not controversial to say that party regulars in both the Democrat and Republican Parties, are not unanimously in support of their party's candidate. Despite Bernie Sander's endorsement of Hillary Clinton, many of his supporters still do not agree with that choice, as indicated by "boos" when Sanders Nominated Clinton for President.
Trump has never been the preferred candidate of Republican Party regulars, but they are unified by their dislike of Clinton. So that appears to be the standoff between the two major party candidates for President. It leaves those of us who are not happy with choosing between Ug or Ick, to look at possible third Party candidates for a better choice.
I have stated already that I am voting for Gary Johnson the Libertarian candidate for President. Johnson has several things going in his favor. He's a fiscal conservative and vetoed a lot of spending bills in his two terms as Governor of New Mexico. As a true Libertarian he believes in smaller government, less wasteful spending, and less governmental control over what citizens can do, as indicated by his support for and use of recreational marijuana. I am not pro-marijuana, but I am against government banning substances primarily for political reasons. Instead of spending megabucks on banning marijuana, tax it like alcohol and tobacco and use the revenue for treatment for abusers to kick the habit.
I am, as most readers can tell from my photographs, an over eater. I've been a lot fatter than I am now and a lot thinner. I'm about ½ way between my highest weight of 299 and my most recent lowest of 148. I'm quite comfortable with my current weight and not making any efforts to lose or gain more. I don't want the government (ya hear me Michelle Obama) meddling in my choice of food any more than it should meddle in someone else's choice of recreational drugs. We all know how terribly wrong the last "noble experiment" went with the prohibition of alcohol in the 1920's. From what I have read Pot is less addictive or harmful than booze, so leave it alone.
Jill Stein isn't as strong an alternative candidate to Hillary as Johnson is to Trump, but at least she is a good alternative; so Bernie's voters who don't like Hillary can vote for Stein. Some will, but even Bernie's disappointed followers probably prefer Hillary to Trump. Hillary also included some of Bernie's goals, like tuition-free college, in her platform to gain his support.
So the question remains, "How much effect will Gary Johnson or Jill Stein have on the outcome of the Presidential election?" The last third party candidate who may have influenced the outcome of a Presidential election was Ralph Nader in 2000. Nader ran on the Green Party ticket. He's been accused of taking enough votes away from Al Gore in Florida for George W. Bush to win the election. My take is that Gore lost because he didn't run a strong enough campaign. It is up to each candidate to run the best, most positive (or negative) campaign that helps them win, and not carp about a spoiler ruining it for them if they lose.