I live in Washington State, and have been divorced for 10 years. In the settlement, I was awarded half of a $40,000 IRA. For one reason or another, that transfer paperwork was never finalized. I have asked my ex about this $20,000, and still have not received it. If I take him to court, can I expect to receive the settlement, plus interest? Or can he claim that the original IRA has lost value, and I am now entitled to half of what it is worth now?

You will probably be awarded half of what it is currently worth unless your divorce settlement specifies a dollar amount,

Depending on what the papers say you might get 1/2 of the original amount adjusted to today's value but not to include any contributions he had made to it in the last 10 years. A lot of IRA's you simply can't cash out unless certain circumstances are in order. Those rules would be governed by the director of the IRA plan itself.