Jill Stein enlisted to help build Cornel West's third-party presidential campaign

Two-time Green Party presidential nominee Jill Stein told CNN on Thursday that she is now assisting Cornel West, the former Harvard professor and longtime progressive activist, as he builds up his recently announced campaign for the White House.

"I'm a transition coordinator helping his campaign move from its previous People's Party context into the Green Party and developing his team and the infrastructure that he needs to run a full-powered, people-powered campaign," Stein said.

West, a prominent surrogate for Vermont Sen. Bernie Sanders during his two presidential campaigns, announced his own plans to run as a candidate with the little-known People's Party in a video earlier this month. But he quickly broke off from that group, which has limited campaign infrastructure amid concerns about ballot access, to join the Greens and seek their nomination.

Stein does not currently expect to have a long-term presence on West's campaign. But her involvement will likely rankle Democrats who say her candidacy siphoned progressive votes from Democratic presidential nominee Hillary Clinton during the 2016 general election - a claim she has always dismissed. In the key swing states of Michigan, Wisconsin and Pennsylvania, Stein's vote total exceeded Donald Trump's narrow victory margins. Still, it is unclear whether Stein voters would have turned out for Clinton had the Green nominee not been on the ballot.

Stein also ran on the Green Party line in 2012, when President Barack Obama was reelected.

Stein said she and others aligned with the Green Party, including her former running mate Ajamu Baraka, reached out to West, through the journalist Chris Hedges, following one of the candidate's early media appearances to offer their help.

"It was really, I think, clear to everyone that Cornel needed to be in a campaign infrastructure that could make this campaign as big as the American people need it to be," Stein said. "We just began the transition at that point, and we are close to moving most of our critical infrastructure and really getting down to work."

Explaining his decision to break from the People's Party last week on the "The Katie Halper Show," West pointed to the Green Party's "broader and deeper" infrastructure and know-how when it comes to ballot access.

"Any candidacy to run the empire, in order to dismantle the empire, has to be part of a movement," West said.

This story has been updated with additional details.