how long is the decision good for and after 20 years is the decision enforceable. what steps should one take when the other party violates the decision?

You would have to refer to your state's Statute of Limitations to find out whether you can still enforce this award. If you can, here is some information on how it can be enforced:

PS - I wish I could comment on whether or not you can enforce the award in your state after 20 years, but the answer is considered "legal advice" and can only be given by a qualified attorney, i.e., a member of the bar in your state. I am not, so cannot comment further.

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