In order for a third party to be viable it will take several election cycles of putting up viable candidates who are allowed to participate in debates and garner recognition for that party's platform and beliefs.
Today most of our elections are determined by political action committees and who raises the most money for negative and defensive advertising.
When people argue a vote for a third party person is a waste what they're really saying is most people are going to vote traditionally.
Therefore a vote for a third party person is going to help or hurt one of the major two parties whose candidates will win.
Truth be told more often than not there are a few third party candidates in every election. In 2012 Gary Johnson was the Libertarian candidate for president and Jill Stein was the Green party candidate.
Neither one of them participated in any of the national debates or received national recognition to share their views with the country. Without publicity no third party can break through.
Have you heard of any of the following: Marc Feldman, Cecil Ince , Steve Kerbel, Darryl Perry, Derrick Michael Reid, and Joy Waymire?
They are all Declared 2016 Libertarian Presidential Candidates!
As of now the Green Party has Jill Stein and Cynthia McKinney.
When people vote they are hoping their candidate will win and effect changes immediately. They don't want to cast a "protest vote".
Therefore someone who supports the Green Party is more likely to vote Democrat believing they will do more for environmental causes. A person who aligns them self with the Libertarian Party is more likely to vote for a Republican because they believe they will work towards having a smaller government and lower taxes.
The only time the media pays attention to a third party candidate is if they are bigger or more well known than the party they represent. (Ralph Nader, Ross Perot, or possibly Donald Trump) otherwise their candidates get no media coverage.
Al Gore lost because he didn't win his own home state of Tennessee! That would be like Reagan losing California, Clinton losing Arkansas, Bush losing Texas, or Obama losing Illinois.
Clinton won Tennessee both times he ran!
Gore got 266 Electoral votes to Bush's 271. Had Gore won his "home state" he would have added 11 electoral votes. 270 is the magic #