The nature of the transaction — the permanent extinguishment of the land claim — is what is being refused.

But the growing fund has a secondary significance that is worth noting.

The longer it sits uncollected, and the larger it grows, the more difficult it becomes for the United States government to argue that the matter has been settled.

The fund’s existence is a constant reminder that the legal obligation acknowledged in 1980 has not been resolved in terms that the people to whom it is owed consider acceptable.

The billion-dollar figure makes that irresolution visible in a way that smaller amounts might not.

It is, in effect, a public accounting — displayed in the Treasury’s records, reported periodically by journalists and researchers, noted in government documents — of a wrong that has been acknowledged and not resolved.