WASHINGTON » In the clearest sign yet of the impact of Justice Antonin Scalia’s death, U.S. labor unions scored a major victory today with a tie vote in a high-profile Supreme Court case they had once seemed all but certain to lose.

The 4-4 split, in a case that sharply divided the court’s liberal union supporters and their conservative opponents, demonstrated how much is riding on President Barack Obama’s effort to replace Scalia with a judge who could tilt the balance on the high court for years to come. Senate Republicans say they won’t consider any nomination until a new president takes office.

The vacancy helped the liberals this time. The deadlocked vote came in a case that considered whether unions representing government employees can collect fees from workers who choose not to join. California teachers backed by a conservative group said being forced to pay union fees violated the free-speech rights of nonmembers who disagree with the union’s policy positions.

The split vote left in place an appeals court ruling that upheld the collection of “fair share” fees from nonmembers.

The result was an unlikely reprieve for organized labor. It had seemed virtually certain that the high court would rule 5-4 to overturn a system that’s been in place nearly 40 years. But the court now is operating with only eight justices after the Feb. 13 death of Scalia, who had been expected to rule against the unions.

The one-sentence opinion issued today did not identify how each justice voted. It simply upheld a decision from the 9th U.S. Circuit Court of Appeals.

But it was a blow to conservative groups that have spent years pushing the court to overrule a 1977 precedent that allows unions to collect fees from members and non-members alike to cover the costs of collective bargaining.

Union officials feared a ruling barring the fees would threaten membership and further weaken the clout of unions, which are major supporters of Democratic candidates and causes. Labor leaders called the lawsuit part of a coordinated effort by conservative groups to weaken labor rights.

The tie vote came amid a political standoff over Obama’s nomination of appeals court judge Merrick Garland to fill Scalia’s vacant seat. Garland was meeting today with Republican Illinois Sen. Mark Kirk, his first meeting with a GOP senator.

White House spokesman Josh Earnest said the 4-4 tie rather than a majority ruling “is not what our founders intended.”

But conservative groups said the split underscored the risk of replacing Scalia with someone more liberal. Confirming Garland would make the court “a rubber stamp not just for the wishes of powerful labor unions, but also for virtually the entire progressive agenda,” said Curt Levey, executive director of the FreedomWorks Foundation.

The union case is just one among a handful of key disputes this term in which Scalia’s vote had been expected to tip the balance toward a conservative result. During arguments in the case in January, Scalia and the court’s four other conservatives had made it clear they were prepared to deal a blow to the unions.

Since Supreme Court decisions are not final until they’re handed down, nothing Scalia did or said in connection with the case before his death mattered in the outcome.

A similar split between the court’s liberals and conservatives was evident last week when the justices heard appeals from faith-based groups objecting to an Obama administration effort to ensure their employees and students can get cost-free birth control. The court today directed both sides to file a new round of legal briefs exploring a possible compromise, setting an April 20 deadline

In the union dispute, the high court had twice before raised doubts about the 1977 precedent, Abood v. Detroit Board of Education. In that case, the court said public workers who choose not to join a union can be required to pay for bargaining costs as long as the fees don’t go toward political purposes.

In 2014, a 5-4 majority stopped short of overturning the case, but the court’s conservatives seemed to invite another full-on challenge.

The lead plaintiff in the latest case was Rebecca Friedrichs, a public school teacher from Orange County, California, who said she resigned from the California Teachers Association over differences but was still required to pay about $650 a year to cover bargaining costs.

Union officials have worried that the potential loss of tens of millions of dollars in fees would reduce their power to bargain for higher wages and benefits for government employees. More than 5 million workers in 23 states and Washington, D.C., are required to pay fair-share fees to public-sector unions that represent them in bargaining. Unions say the fees are necessary because the organization has a legal duty to represent all teachers, even those who are not members of the union.

Associated Press writer Darlene Superville contributed to this report.