Big Labor pumped $530 million of workers’ dues into mostly Democratic Party groups and liberal causes over a four-year period — with dismal results, according to a new analysis.

Despite the unions’ massive cash infusion into Democratic causes, GOPer Donald Trump still won the union-heavy Rust Belt states of Pennsylvania, Michigan and Ohio in his presidential bid against Dem candidate Hillary Clinton. A Republican-led Congress, expected to be hostile to union causes, also was voted into office.

“Labor unions have become the ATM of the Democratic Party — despite the known fact that 40 percent of union households vote for Republican candidates,” said Richard Berman, director of the Center for Union Facts, a group typically critical of unions which conducted the study.

“On top of direct super PAC donations to Democrats, Big Labor hijacks members’ dues money to bankroll hundreds of liberal special interest groups,” Berman added.

The group’s analysis reviewed tax filings from 2012 to 2015 to see how much the country’s major labor unions — including the AFL-CIO, teachers and public-employee unions, Teamsters, Auto Workers and Steelworkers — donated to union-friendly and left-liberal groups that promote their agenda. Filings for 2016 are not yet available.

The review found that the unions plowed $529.9 million into the groups and causes from 2012 to 2015.

Based on what was spent in previous years, the unions likely donated another $140 million to allied groups in 2016, bringing the total to $670 million over five years.

A total of $260.4 million went to 45 different party or Democratic-leaning groups, including the Bill, Hillary and Chelsea Clinton Foundation, Democratic Attorneys General Association, the Working Families Party, the Center for American Progress and Planned Parenthood.

More than $21.5 million went to left-leaning civil rights groups including Al Sharpton’s National Action Network, Jesse Jackson’s Rainbow PUSH Coalition, National Council of La Raza and the NAACP.

The report also found that unions funneled a combined $196.5 million to liberal economic and environmental groups, including Fiscal Policy Institute of NYC, Greater NY Labor-Religion Coalition, and Make the Road NY.

In addition, recipients of the dough included NY Communities for Change, formerly ACORN, which received $2 million in 2015. NYCC works closely with the teachers’ union and campaigns against charter-school expansion.

Another $44.5 million went to what the Center for Union Facts claims are “special interests,” including the Alliance for Quality Education, a teachers’ union-allied group.

Labor leaders defended the spending and dismissed the report as coming from an anti-labor, right-wing group.

“There’s no second-guessing how we spent the money. It’s crucial for working people’s voices to be heard in the political process,” said Stuart Appelbaum, president of the Retail, Wholesale and Department Union and a member of the Democratic National Committee.

He said unions will have to band together more than ever in the Trump era.

“There will be attempts to weaken the bargaining power of working people,” Appelbaum said.