Democratic presidential candidate Bernie Sanders, wearing a Warriors cap, speaks during a campaign rally at Oakland's City Hall  in California on May 30. (Anda Chu/Oakland Tribune via AP)

SPRECKELS, Calif. — When the Democratic National Committee announced that Sen. Bernie Sanders of Vermont would get to pick five of the 15 people who'll write the party platform, it was seen as a small coup. But at a news conference today, Sanders revealed that the DNC had actually vetoed his nomination of a key labor ally, and said he was told not to pick anyone else from the labor movement.

“What we heard from the DNC was that they did not want representatives of labor unions on the platform-drafting committee,” he said. “That’s correct.”

Yesterday, Wall Street Journal reporter Peter Nicholas was the first to report that Sanders had included RoseAnn DeMoro,  executive director of National Nurses United, on his list of preferred platform committee members. "He told me that he really wanted me on the committee to advocate for Medicare for All, especially," DeMoro told The Washington Post today.

According to Sanders and DeMoro, the DNC nixed her, resulting in a Sanders delegation of four men, one woman (Native American activist Deborah Parker), and no one from organized labor. While many progressive commentators cheered Sanders's picks, which include the environmental writer and activist Bill McKibben and the academic iconoclast Cornel West, the gender and work balance opened him up to criticism.

"I think it was a set-up," said DeMoro. "It fed into the 'Bernie bro' narrative and meme -- oh, Bernie picked one woman, he's a sexist. As soon as the list was out, there were articles about how he chose two 'anti-Israel' people. The truth of the matter is that they were choices the DNC had signed off on."

In an interview  Wednesday, DNC platform committee spokeswoman Dana Vickers Shelley confirmed that the DNC had not wanted labor leaders on the platform drafting committee, limiting labor's presence to Paul Booth of the American Federation of State, County, and Municipal Employees union.

“Because union leadership was represented on the full platform committee, a decision was made no union leadership would be represented on the platform drafting committee,” said Vickers Shelley. “That was communicated to the campaigns, and they understood our rationale.”

That was cold comfort to DeMoro. "The most insidious thing, frankly, is that only one of 15 people on this drafting committee is for labor," she said. "It shows you how insidious the DNC has become. Labor built this party. Labor built this country. One person is enough to represent all of that? If you look at the composition of who they chose, besides Bernie’s choices, K Street’s far better represented than the labor movement."

Juliet Eilperin contributed reporting from Washington.