Any state that wants to do this is going to run into a few problems, a major one being people who rely on their SS for income. Assuming that SS payments would just stop, and that residents would no longer have federal taxes withheld from their paychecks, an idea to fix this is to sanction legitimate charities with the ability for donors to set up withholding for whatever amount the donor wishes to donate.
Showing what a lie and a joke SSI are. Logically the government has been telling me that is MY retirement fund, based on my (and my employers) contributions. So what if Wyoming opts out. The Social Security Administration / Trust Fund still has (IMHO) a moral duty to pay back individuals who have paid in what they are owed. If they didn't, a lot of retirees would move to a state still participating in the system, or at least rent post office boxes in Denver.
Agreed on the moral duty considering what they’ve promised, but the charity idea would most likely more than replace the money necessary for people who really needed SS to live on.
Others, who just wanted it because they felt it was owed to them, can get a Denver PO box.
If you’re gonna cut ties, you have to cut them, not quibble over money that was spent long ago.