Public sector unions triumphed before the U.S. Supreme Court on Tuesday when the justices preserved a vital source of cash for organized labor, splitting 4-4 on a conservative challenge that had seemed destined for success until Justice Antonin Scalia's death last month.

The case brought by nonunion public school teachers in California had targeted fees that many states force such workers to pay unions in lieu of dues to fund collective bargaining and other activities. A loss in this case would have deprived unions representing teachers, police, transit workers, firefighters and other government employees of millions of dollars annually and diminished their political clout.

The outcome illustrated the impact on the court of the Feb. 13 death of Scalia, the long-serving conservative justice who almost certainly would have cast a decisive vote against the unions. But by virtue of splitting 4-4, the justices affirmed a 2014 lower-court ruling that allowed California to compel nonunion workers to pay the fees.