Joe Schoffstall and Patrick Hauf of the Washington Free Beacon tally union financial support for the 2020 Democratic presidential candidates.

Democratic presidential candidates have hauled in hefty campaign contributions from organized labor throughout their political careers.

The Democratic presidential candidates have combined to receive $12.5 million from organized labor during their time in public office, according to a Washington Free Beacon review of state and federal campaign records. The presidential hopefuls are now jockeying for union endorsements and attempting to win over the sector to secure pivotal voters and volunteers in a crowded primary. Staffers from two campaigns, Sen. Bernie Sanders’s (I., Vt.) and former secretary of Housing and Urban Development Julián Castro’s, have unionized. Many top unions are in no rush to endorse in a field full of familiar allies.

“With this many candidates running, working people can afford to be selective with our vote,” John Weber, press secretary for the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO) told ABC News in May. “We’re looking for a candidate who understands that the single best way to make our economy fairer is by making it easier to join a union. If your first priority isn’t fighting for working families, we’re not interested.”

Former vice president Joe Biden garnered the cycle’s first big endorsement from the International Association of Fire Fighters. The former Delaware senator, however, is far from the top beneficiary of union cash out of the candidates seeking the party’s nomination. Despite having been involved in politics longer than most in the primary, Biden’s campaigns have received a combined total of just $363,499 from labor, according to sector data compiled by the Center for Responsive Politics.