On Tuesday, the Supreme Court of the United States, stuck in a 4-4 deadlock, affirmed the lower court’s decision in Friedrichs v. California Teachers Association, a labor union dues case.

The one sentence decision offered no explanation and simply stated, “The judgment is affirmed by an equally divided Court.”

Should public employee unions be able to impose mandatory dues?

At issue in the case was a challenge to the power of public employee unions to impose mandatory dues, an issue that has been bitterly fought by both sides of the labor union debate. Tuesday’s ruling allows the unions to continue to collect dues for collective bargaining costs, pursuant to a prior case from 1977 that allowed these mandatory dues, so long as the employees were not forced to pay for political or ideological activities.

Bloomberg Politics reported that the California teachers who challenged the mandatory dues were paying dues that “often exceed $1,000 a year per employee,” and those who objected to the union’s political activities could request a refund of about $350 to $400.

The pro-labor union side, including the teachers’ unions, California Attorney General Kamala Harris, and the Obama administration, had argued that forcing all employees to pay the dues prevents “free riders” who would get benefits like pay raises without paying for the costs of the unions.

Attorneys representing the teachers challenging the mandatory dues in this case and similar ones offer the counterargument that it is the unions who are getting the free ride on the backs of employees who do not support their politics. Even if an employee refuses to support the union’s political activities, the hundreds of dollars each teacher is forced to pay the union allows it to cover administrative and other expenses, and frees up other funds for political activities.

It’s a similar argument as that used by the opponents of taxpayer funding for Planned Parenthood, even though those funds are technically prohibited from being used for abortions. Every dollar that goes to non-abortion services frees up another dollar that can be spent on abortions.

Ripple effects from Scalia’s death

If Justice Antonin Scalia had not died earlier this year, and the full nine members of the Court had been able to vote on the case, many Court observers had expected a 5-4 ruling, against the labor unions. From the Wall Street Journal:

During oral arguments in January, the court’s five conservative justices, including Justice Scalia, appeared poised to overturn a 1977 decision allowing public-employee unions to collect dues from workers for collective bargaining costs. Indeed, conservative Justice Samuel Alito in a 2014 ruling all but invited a challenge to the nearly 40-year-old precedent.

Instead, with Scalia’s seat on the bench still open, the Court has been forced to issue rulings with only eight Justices, and in the case of a tie, the lower court ruling stands, but does not become binding Supreme Court precedent. This is what happened in Friedrichs.

Prior to the Court’s ruling, attorneys with the Center for Individual Rights, a conservative legal group opposing the mandatory union dues, had announced that they intended to file a petition for rehearing in the event of a 4-4 decision. SCOTUSblog reported that such a petition is, in fact, being filed.

It is rare for the Court to grant such petitions. Success requires getting five Justices to support the petition, including at least one who joined in the decision. If granted, the case would most likely be postponed to the Court’s new term, scheduled to begin October 3rd, 2016.

November’s election casts a shadow over the Court

President Obama has nominated Judge Merrick Garland of the U.S. Court of Appeals for the District of Columbia Circuit to fill Scalia’s seat, but Senate Republicans have vowed to block any nominations until after the November 8th general election. If they hold firm, Garland or any other nominee may not be able to be approved in time to participate in a rehearing in Friedrichs in time to issue an opinion this time next year.

Moreover, Friedrichs is far from the only legal challenge to mandatory public union dues. Regardless of what happens with the petition for rehearing or Garland’s nomination, the issue is not going away. With the Court’s deadlock decision failing to set binding precedent and hundreds of millions of dollars at stake in union coffers around the country, it is not a matter of if, but when the Court will having this debate again.

Follow Sarah Rumpf on Twitter: @rumpfshaker.