Local and State government employees are exempt from Social Security and Medicare (Constitutional issue), but they may elect to participate as those government may determine. At one time, the military was also exempt, but that ended in 1957.
As local and perhaps even state governments begin to collapse, they will try to get the federal government to bail them out and will no doubt invent some story that the mean federal government shut them out of Social Security and so they deserve to be rescued. Politicians, of course, will sign up for this fiction.
Wait until Illinois files BK. There’s going to be 100s of thousands like this.