The California Nurse’s Association (CNA) has endorsed Bernie Sanders for president in a push to boost the Democratic candidate’s campaign ahead of the state’s primary.

RoseAnn DeMoro, executive director of the union, says the union is often underestimated because they are women.

Thus far, the union has represented Bernie at many protests, but many question whether this will be enough to have an impact. The California Nurse’s Association has 900,000 members in the state.

In 2010, the union disrupted Meg Whitman’s campaign for California governor. The CNA called out Whitman for having an illegal immigrant as a housekeeper, and claimed her campaign supported “education for the few,” “healthcare for the rich,” and “prisons for all.”

California will hold its primary on June 7, and will be the deciding state in whether Clinton clinches the nomination.

The Los Angeles Times says that through the union’s super PAC, the group has spent over $2.4 million to back Sanders through the hosting of rallies, placing billboards and setting up phone banks.

California residents have until May 23 to register. The Democratic primary is open both to Democrats and those who do not have a party affiliation. There are 475 delegates up for grabs in the state.