Pat Stogran posted a video Saturday on YouTube, saying the inside workings of the NDP are "fundamentally flawed.''
"The fight to take on politics incorporated while also trying to take on the insiders of a political party that has no desire to see me win has proven insurmountable,'' he said in the five-minute video.
He also said the party has put "major obstacles'' in place for candidates trying to grow the party's base from the grassroots.
Stogran is a retired Canadian Armed Forces colonel who served for over 30 years, including in Afghanistan, and said serving for the greater good was his "calling in life.''
Pat Stogran is shown at a news conference in Ottawa in 2010. (Photo: Sean Kilpatrick/Canadian Press)
He acquired a reputation for being outspoken as the former federal veterans ombudsman under the former Conservative government.
He announced his bid to run in the NDP's leadership race in April.
But in his video, Stogran said, "As I enter my golden years, I came to the conclusion that my love for family far outweighs my love for politics, especially selfish, incompetent politics.''
Stogran said the NDP will never form a government until the party itself is reformed and he doesn't see any possibility of reform.
"As I enter my golden years, I came to the conclusion that my love for family far outweighs my love for politics, especially selfish, incompetent politics.''
He said he resigns with "huge sadness'' from the race, and thanked his supporters and campaign team that stood behind him in his effort "to defeat politics incorporated.''
Leadership candidate and MP Peter Julian tweeted, "Sad to learn that @PatStogranNDP is withdrawing from the #NDPldr race — thank you for your contribution to the debate.''
Party officials did not immediately respond to requests for comment.
There are now five official candidates in the race to succeed current leader Tom Mulcair, who didn't survive a leadership review.
Watch Stogran's video above.
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