This was federal court, meaning the plantiffs were making a U.S. Constitutional argument. However, there's a clear, longstanding record on education largely not being covered under the U.S. Constitution; it is reserved to the states under the Tenth Amendment to the Constitution. The case generally cited on this is San Antonio Independent School District v. Rodriguez, which at heart was a school finance case, arguing that the Texas funding system, being heavily dependent on property taxes (sound familiar?) was a violation of the equal protection clause of the Fourteenth Amendment. The Supreme Court found, 5-4, that the system did not violate the equal protection clause and there was not fundamental federal right to an education.
This is why most cases on school funding are made in state courts, citing state constitutions' language on education. In the case of Michigan, this had already been tried, citing the Michigan constitution:
That constitutional provision states that "the means of education shall forever be encouraged," and "the Legislature shall maintain and support a system of free elementary and secondary schools."The earlier case was decided against the plantiffs:
But the Michigan Court of Appeals dismissed that lawsuit in 2014, saying:And the Michigan Supreme Court declined to take up the case on appeal.
"The cited provisions of the Michigan constitution require only that the Legislature provide for and finance a system of free public schools. The Michigan constitution leaves the actual intricacies of the delivery of specific educational services to the local school districts."
Note that in all of the above cases, the responsibility of the state to have schools was not under question. What the constitutional parameters (both state and federal) of that responsibility requires is what was being decided. The case decided this week doesn't appear to much change what we already knew of the federal responsibility.
as always, I'm not a lawyer...I just spend time following this stuff.