Justice Clarence Thomas, Elena Kagan, Samuel Alito and Chief Justice John Roberts (Getty Images/Chip Somodevilla)

On its way to ruling by a 5-4 majority that the Secretary of Commerce improperly decided to include a citizenship question in the 2020 Census, the Supreme Court unanimously concluded that states had legal standing to sue the federal government over this issue based on the court’s conclusion that it is “predictable” that noncitizens will act “unlawfully” by declining to fill out the Census questionnaire.

The court explained its conclusion on this question in Part II of its opinion, which all nine justices joined.

“To have standing,” Chief Justice John Roberts wrote in this unanimously-joined part of his opinion in Department of Commerce v. New York, “a plaintiff must present an injury that is concrete, particularized, and actual or imminent; fairly traceable to the defendant’s challenged behavior; and likely to be redressed by a favorable ruling."

What injury did the states that sued the Department of Commerce over the secretary’s decision to include a citizenship question in the 2020 Census claim they would suffer because of this decision?

“Respondents assert a number of injuries—diminishment of political representation, loss of federal funds, degradation of census data, and diversion of resources—all of which turn on their expectation that reinstating a citizenship question will depress the census response rate and lead to an inaccurate population count,” the Supreme Court said.

In its brief to the court, the federal government had argued that these injuries that states said they would suffer would result not from any action taken by the federal government itself but from the actions of noncitizens who choose—illegally—not to participate in the Census.

“As the government has explained,” Solicitor General Noel Francisco wrote in his brief to the court, “respondents do not have standing because their alleged injuries will materialize only if unidentified third parties react to the citizenship question by illegally refusing to fully answer and return the census questionnaire in violation of federal law, see 13 U.S.C. 221.”

“Accordingly,” Solicitor General Francisco continued, “respondents’ alleged injuries would not be ‘fairly attributable’ to the Secretary’s decision to reinstate the citizenship question to the decennial census; they would be attributable to the unlawful decision of these independent third parties.”

The unanimous Supreme Court did not rebut the conclusion that the injuries suffered by the states would be triggered by the illegal acts of noncitizens deciding not to participate in the Census. Instead, it concluded that because these illegal acts were a predictable result of the Census including a citizenship question, the states could still sue the federal government over the question.

“The government contends, however, that any harm to respondents [the states] is not fairly traceable to the Secretary’s decision, because such harm depends on the independent action of third parties choosing to violate their legal duty to respond to the census,” said the court.

“The chain of causation is made even more tenuous, the government argues, by the fact that such intervening, unlawful third-party action would be motivated by unfounded fears that the federal government will itself break the law by using noncitizens’ answers against them for law enforcement purposes,” the court continued.

“The government,” the court said, “invokes our steady refusal to ‘endorse standing theories that rest on speculation about the decisions of independent actors,' particularly speculation about future unlawful conduct.”

“But we are satisfied,” Roberts said for a unanimous court, “that, in these circumstances, respondents have met their burden of showing that third parties will likely react in predictable ways to the citizenship question, even if they do so unlawfully and despite the requirement that the government keep individual answers confidential.”

“Respondents theory of standing thus does not rest on mere speculation about the decisions of third parties; it relies instead on the predictable effect of government action on the decision of third parties,” said Roberts for the unanimous court.

In Part V of the decision, the court ruled 5 to 4—with Justices Ruth Bader Ginsburg, Elena Kagan, Stephen Breyer and Sonia Sotomayor joining Chief Justice Roberts—that the citizenship question should be thrown out. These justices came to this conclusion not because they argued it was unconstitutional for the census to ask the question, and not because the they believed that by including the question the Secretary of Commerce had violated the law giving him discretion over the content of the census.

The five justices came to their conclusion because they did not like the manner in which they perceived the Secretary came to this conclusion.

“We do not hold that the agency decision here was substantively invalid,” Chief Justice Roberts conceded on behalf of these five justices.

“But agencies must pursue their goals reasonably,” he wrote. “Reasoned decisionmaking under the Administrative Procedures Act calls for an explanation for agency action. What was provided here was more of a distraction.”

Justices Clarence Thomas and Samuel Alito both wrote opinions rebutting the court’s opinion invalidating the citizenship question and its authority to make it.

“For the first time ever,” wrote Thomas, “the court invalidates an agency action solely because it questions the sincerity of the agency’s otherwise adequate rationale.”

Alito concluded that the court had no legal basis to challenge the Secretary of Commerce’s decision. “If the secretary violates the Constitution or any applicable statutory provision related to the census, his action is reviewable,” wrote Alito.

But, said Alito: “Whether to put a citizenship question on the 2020 census questionnaire is a question that is committed by law to the discretion of the Secretary of Commerce and is therefore exempt from APA review.”