The committee voted Councilman Mel Witherspoon off the committee after he refused to resign.
Witherspoon supports fellow councilman and longtime friend John Evans, the only Republican running for council on Nov. 5, the Erie Times-News reported.
Three other Democrat incumbents and another Democrat challenger are also on the ballot, meaning five candidates are vying for four council spots in a city where Republicans are seldom elected.
Witherspoon isn't up for re-election this year. Evans was appointed to fill a vacancy last year and is now running for a full four-year term.
"I've been friends with him for more than 20 years and he's highly qualified," Witherspoon said of Evans.
Evans said he was "delighted" by Witherspoon's support, "but I'm sorry that anyone would pay a penalty to support someone they believe in."
"It's unfortunate that people are still stuck in the old ways of saying, 'Party first,'" Evans said. "I thought at the local level we'd gotten smarter than that."
Bill Cole, the county Democratic chair, said that while he understands Witherspoon's decision, the party bylaws can't be ignored.
"Let me put it to you this way," Cole said. "You can't be on the Pittsburgh Steelers defense and block for the Cleveland Browns running back because you think he's the best running back on the field."