"Fight for $15" protesters brave the rain in Baltimore. The SEIU led this campaign. (Win McNamee/Getty Images)

After the election of President Trump, one of the country’s largest and most politically active unions is preparing to slash nearly a third of its budget. 

Conservative outlets this week reported the Service Employees International Union has started laying off employees at its Washington headquarters — a claim the labor giant has denied — and that its coming cuts, made public last December, could be related to its significant political spending in the 2016 presidential campaign.

 “After spending big on Clinton, Obama, SEIU now facing steep budget cuts,” the Free Beacon published, referencing a recently posted federal filing and launching a flurry of aggregated posts.

But connecting those events — SEIU’s support of Democratic politicians and its upcoming cuts — is misleading, said Joseph Slater, a labor-focused professor at the University of Toledo’s College of Law.

“This isn’t a union financially in trouble because of money spent on the election,” Slater said. “That money was budgeted for the election, and the SEIU has a long history, as do most other labor unions, of supporting candidates.”

Rather, he said, the union is bracing for a monetary blow in the near-future — brought on, in part, by Trump's Supreme Court pick.

Judge Gorsuch, who was sworn in this week, could cast the deciding vote in a case that concerns whether public sector unions can collect “agency fees” from workers who don’t want to bankroll the union’s political activities. One such case in Illinois could land before the court as early as this year.

Union leaders see attempts to relieve workers from payments as an attack on the core principle of the labor movement — that workers who enjoy a union's protection shouldn't be “freeloaders.”

In the latest high-profile attempt to change this norm, first established in the Supreme Court 40 years ago, a group of teachers in California last year argued their free-speech rights should release them from having to pay dues to the state's teachers' union.

The Friedrichs v. California Teachers Association, which arose just after the death of Justice Scalia, ended in a 4-4 tie, upholding the court's old precedent.

Republicans blasted the decision, asserting unions shouldn’t be able to force people to fork up cash, while Democrats said that union dues are vital to securing the best pay and benefits for workers.

For the SEIU, which represents about 2 million government, health-care and service workers — half of whom are employed in the public sector — lost member fees would create a significant income hole.

The union has historically poured serious money into Democratic candidates and causes. In 2016, the union spent about $61.6 million in the political arena, which comprised about 20 percent of its total expenditures. It also led the “Fight For $15” campaign, pushing liberal politicians farther left in the minimum wage debate.

During the last election cycle, however, the union floated less support than usual to the Democratic nominee. The SEIU gave $23,069 to Hillary Clinton (and $19,600 to Bernie Sanders) last year, $72,047 to Barack Obama in 2012 and $50,348 to John F. Kerry in 2004. 

Then Trump won and, breaking tradition, some unions celebrated his victory. That’s because the real estate titan built much of his campaign on slamming companies for outsourcing jobs and pledging to revamp trade deals, plus American manufacturing and infrastructure.

Janice Fine, a labor professor at Rutgers University, said the union universe is split on Trump, with the largest division forming between those that represent the public sector and those that serve building trades.

“You see these construction trade leaders grinning and shaking hands with President Trump in the Oval Office,” she said, while a union like the SEIU needs to build a nest egg for the challenges his administration may pose. 

The SEIU has called the Trump White House a “threat” to the labor movement and said its plan to shrink its budget by 30 percent this year is part of a broader strategy to save up for imminent battles.

“These particular budget cuts are our way of enacting financial efficiencies to deal with the realities posed by extremist right wing labor policy in all branches of the federal government,” said union spokesperson Sahar Wali in an email to the Post, “and still implement our plan to win for working people.”

Wali declined to comment further on the union’s next steps or campaigns, adding that the board will determine what, exactly, is cut in a June meeting.

Meanwhile, any Republican-led slashes to Medicare or Medicaid could damage the paychecks of home health aides, many of whom the SEIU represents, since private nursing homes and hospitals, for example, are reimbursed through the government programs.

“This is a watershed moment,” said Tom Juravich, director of the Labor Center at UMass Amherst.“What they’re saying with budget cuts is: We need to anticipate this. We need to put some money aside for the kinds of changes that would be catastrophic.”