MANCHESTER, NH -- Former two-term New Mexico Gov. Gary Johnson officially dropped out of the Republican race for the White House today to run for the Libertarian Party's nomination.
Johnson said he's "deeply disappointed" by the GOP in a process he deemed "not fair." His campaign first announced the shift last week.
"Frankly, I have been deeply disappointed by the treatment I received in the Republican nomination process," Johnson said at his announcement in Sante Fe. "The process was not fair and open."
Johnson is the first major candidate to run as a third-party candidate. His jump comes after serving as New Mexico governor as a Republican from 1995 to 2003 and months of campaigning in New Hampshire, where he was unable to rise above low single digits in state-wide polls. Johnson was famous for criss-crossing the state on his bicycle and hosting a town hall meeting in Concord -- to which no one showed up.
Nationally, Johnson has been known for supporting the legalization of marijuana. Unlike most of his GOP counterparts, he also supports gay marriage and abortion rights.
As a libertarian-minded candidate, Johnson often had a difficult time escaping the shadow of the more popular Texas Rep. Ron Paul, who champions similar positions as Johnson. Paul has told NBC News he has no intentions of running as a third-party candidate, but did not completely rule it out if he is unsuccessful in his Republican bid.
Johnson said Paul's potential failure to win the GOP nomination was part of his own calculus to run as a Libertarian.
"While Ron Paul is a good man and a libertarian who I proudly endorsed in 2008, there is no guarantee he will be the Republican nominee," Johnson said.
Johnson said moving to the Libertarian Party was "both a difficult decision -- and an easy one."
"I have a lot of Republican history and a lot of Republican supporters. But in the final analysis ... I am a Libertarian -- that is someone who is fiscally very conservative but holds freedom-based positions on the issues that govern our personal behavior," he explained.
If Johnson wins the Libertarian Party's nomination, his name would appear on the general election ballot in all 50 states.