Well... the US, for various reasons, does not have the mechanisms for serious multiple party candidates. There are numerous 'other' parties, but no way to officially give them some % of seats in Congress related to the number of votes.

The system allows all 50 states to conduct elections using local rules, but when national elections are held, all we are actually voting for are 'electors' who convene and vote for candidates they are committed to in the 'electoral college'

"Most states have a "winner-take-all" system that awards all electors to the winning presidential candidate. However, Maine and Nebraska each have a variation of "proportional representation."

This was a fine system in the 1700s, but it now distorts and fails to recognize the wide range of actual voters opinions. There is no way to formally form coalitions, as they do in Israel, for example.

Any moderately successful 3rd party can merely steal votes from the major party they are closest to. Several times this has resulted in the candidate who got the largest # of national votes actually losing... depending on which states he won.... as in Bush v. Gore. Ralph Nader is widely thought to have been a major reason Gore lost in 2000.

"The Greens gained widespread public attention during the 2000 presidential election, when the ticket composed of Ralph Nader and Winona LaDuke, won 2.7% of the popular vote. Nader was vilified by some Democrats, who accused him of spoiling the election for Al Gore. Nader's impact on the 2000 election has remained controversial.?

This is why Bernie Sanders entered the Democratic race.

Now... as closely as I follow politics, I had NOT heard of the Justice Party. When I read their platforms and issue statements, what hits me is that even though they are 'liberal', much of what they say is negative... like this from Rock Anderson...

********************************************************************
"Hillary Clinton is the presumed front-runner for the 2016 presidential
election. She has a recognized reputation for lying, distorting, and evading.1   

The American people deserve better -- they deserve the truth -- but they
won't get it if the media continues its lazy and/or timid (often seemingly
driven by bias and even complicity) inquiries of Hillary Clinton.   

These are issues of war and peace, of life and death, of fundamental human
rights and economic justice, of integrity, of the habitability of the earth --
and the next President of the United States has a crucial, perhaps a
dispositive, role.   

Please, Journalists: Ask the questions competently and persistently -- and
get the answers, finally, for the American people.

                                                
1
"A recent Gallup Poll found that 53 percent of Americans think Clinton isn't 'honest and trustworthy.'
Steven Thomma and William Douglas, "Is Hillary Clinton dishonest? A lot of Americans think so,"
Gazette.com, April 5, 2008 (http://www.freerepublic.com/focus/f-news/1997528/posts ). "Issues of honesty
have dogged Clinton for years. In this week's poll, a third of Americans says she has less honesty and
integrity than most people in public life." Kathleen A. Frankovic, "Reputation Audit: Hillary Clinton,"
YouGov, February 27, 2014 (https://today.yougov.com/news/2014/02/27/should-hillary-run/ )
**********************************************************************

Now, what I read there tells me nothing about WHY he is painting Ms. Clinton negatively.... it merely cites polls reflecting how thoroughly the IDEA that she is not considered 'honest and trustworthy' has been inserted into the discorse. To me, this is condemnation by insinuation and implication.
When I listen to her, I don't see this... and... one of the politicians I DO trust, Senator Al Franken, has praised her highly, both for competence and for honesty...and Franken gives specifics.

I am sure that parties like Green & Justice.. and even Libertarian.. have many good ideas and principles I can agree with, and I'd like to see some way they could be recognized without simply being 'spoilers'.