Last week’s U.S. Supreme Court ruling that Philadelphia’s decision to exclude Catholic Social Services from foster care placements infringed the religious freedom of the agency and the foster parents it partnered with was unanimous. The official Court document, however, contained four different opinions, an “opinion of the Court” (or majority opinion) and three additional “concurring” opinions.

The most substantial of these additional opinions was written by Justice Samuel Alito and joined by Justices Clarence Thomas and Neil Gorsuch. At 77 pages it is more than five times as long as the majority opinion. Why did Justice Alito write a separate opinion, and especially such a long and detailed one, if he agreed with the outcome the majority announced?

The practice of issuing written decisions to explain the reasoning of a court decision has important advantages.

Article III of the Constitution provides for a Supreme Court and allows Congress to create lower courts. In our federal current system, these latter types of court include a district court which handles the initial fact-finding and application of current law to specific circumstances. The decisions made by the district can be appealed to the court of appeals, regional courts that review the district court opinions to ensure that they are consistent with the relevant laws and do not overstep the authority of the lower court. The Supreme Court can review these decisions as well as final decisions in the state court system that implicate federal laws, including the Constitution.

In practice, this means that the decisions of the U.S. Supreme Court are used by lower courts to determine how a specific constitutional or statutory provision should apply in circumstances similar to those the Supreme Court has already ruled on.

This is intended to ensure that a federal court ruling on the meaning of a federal law is not dependent on the geographic location of where the case originates. It promotes uniformity throughout the federal system and consistency in the application of constitutional provisions and other federal laws throughout the nation.

For instance, equality in the law would be impossible if the Fourth Amendment were interpreted to allow Georgia citizens to be searched without cause but citizens in Minnesota were guaranteed protection from such a search. This consistency is a hallmark of the principle of a rule of law. If it works as it should, the result of a similar disputes in Rhode Island and California should be the same.

The practice of issuing written opinions describing the reasoning of the judges also gives guidance in future Supreme Court decisions so the consistency so important to the stable application of the law is not dependent on shifting trends over time.

Finally, those who are impacted by the application of laws will have notice of whether their conduct violates the law. For instance, attorneys representing a school that is considering disciplining a student for derogatory comments about the school on social media should notify the school of a Supreme Court decision earlier this week finding a school in violation of the First Amendment for doing just that.

Without the practice of giving reasons for a court’s decision and the related practice of lower or later court decisions applying those reasons, those involved in legal disputes would be at risk of arbitrary results since each case, no matter how similar to others already decided, would have to be decided in isolation.

So, what is the role of separate opinions? These are written by justices who either disagree with the majority and want to explain why (dissenting opinions), justices who agree with the majority but want to add some observations they think should be considered in other cases (concurring opinions), or who agree with the result but not the reasoning of the majority and want to offer an alternative reason for that result (opinion concurring in the judgement).

These types of opinions can be important in shaping later decisions of the Supreme Court on similar or related issues. For instance, the infamous 1896 Supreme Court decision Plessy v. Ferguson endorsed the idea that racial segregation was constitutional as long as facilities provided to separate races were equal (separate but equal). Justice John Marshall Harlan dissented from the majority opinion: “The law regards man as man, and takes no account of his surroundings or of his color when his civil rights as guaranteed by the supreme law of the land are involved.” That reasoning was eventually adopted when the Supreme Court abandoned the Plessy decision in Brown v. Board of Education which ended official segregation.

Which brings us back to Justice Alito’s concurring opinion in Fulton v. Philadelphia. Justice Alito agreed with all of the other justices on the court that Philadelphia’s treatment of Catholic Social Services (CSS) was unconstitutional. He did not, though, agree with the majority’s reason for that decision.

The majority focused on two unique aspects of the Philadelphia law: the fact that it allowed for the city to make exceptions to the normal foster care agency rules, and the fact that the city’s public accommodations law did not cover foster care accreditation. For the majority, then, the unequal treatment, not the burden on religious exercise was the reason for its decision.

That is what prompted Justice Alito’s concurrence. He expressed the concern that the city could go back and change the law to address the concerns identified by the majority and then exclude CSS again.

To illustrate the danger of this possibility, one need only note that Jack Phillips, the cake decorator involved in a 2018 Supreme Court decision, Masterpiece Cakeshop v. Colorado Civil Rights Commission, has continued to experience legal persecution since that decision. The Supreme Court decision had focused on the unique circumstances of Phillips’ original administrative hearing and the biased opinions expressed by the Colorado Civil Rights Commission as the reason for its ruling that Phillips’ First Amendment rights were violated. So, subsequent discrimination complaints against Phillips for failing to create cakes endorsing messages inconsistent with his religious commitments have avoided the same types of comments but came to the same conclusion – that Phillips has to advance messages that violate his beliefs.

Thus, Justice Alito would have had the court address a more fundamental issue: when a government imposes a burden on religious exercise, can the court assume that the burden is unconstitutional unless the government can show a compelling need for it? This would prevent a scenario where a motivated government could just adapt laws to continue to impose burdens on religious exercise.

So, Justice Alito’s opinion makes a comprehensive case for the constitutional standard he thinks should apply in religious freedom cases. The opinion is long because it examines the meaning of the constitutional text, history and legal developments over time. Two other justices agreed with his analysis and two others suggested they were open to something like it in a future case. So, this concurrence could end up becoming important in a future legal dispute.

Like Justice Harlan’s dissenting opinion in Plessy, Justice Alito’s concurrence in Fulton may yet come to rule the day. In the vacuum of current Congressional inaction on these important policy issues, only time and the direction of the Supreme Court’s legal thinking will tell.