The California Rule on pensions

An employee’s vested contractual pension rights may be modified prior to retirement for the purpose of keeping a pension system flexible to permit adjustments in accord with changing conditions and at the same time maintain the integrity of the system. Such modifications must be reasonable . . . . To be sustained as reasonable, alterations of employees’ pension rights must bear some material relation to the theory of a pension system and its successful operation, and changes in a pension plan which result in disadvantage to employees should be accompanied by comparable new advantages.

This is a contract law case, not a fundamental rights case. The Supremes  identified an understood verbal agreement in the employee contract.

But that contract is voluntary for individuals and their local legislature. The voluntary nature of contracts is fundamental and local cities are free to reject the California Rule in writing and by legislation for new hires. That is a fundamental right, contracts are voluntary expression of assembly and the prohibition against illegal takings.

Either cities and individuals are free in their voluntary contract selection or not. If not, then let the US Supremes decide the powers between state and fundamental rights.  But the battle is won on the human rights issue, the individual has to file on behalf of himself, and a class or individual humans.  The court is not doing any more Citizen's United, they are getting burned badly on that blunder.