Ducey has disputed that. He even got former Congressman John Shadegg to testify to a legislative committee that a 1999 amendment to the 1912 Enabling Act is broad enough to allow Arizona voters, by amending the state Constitution as they did in Proposition 123, to decide how they want to spend the trust without getting further federal approval.

In fact, Shadegg told lawmakers that he reads that 1999 amendment to allow voters to drain the entire trust if they want.

Proposition 123 does not go that far. But it does impact the account.

Legislative budget staffers said that without approval of Proposition 123 and a change in the withdrawal rate, the fund would grow to about $9 billion by 2025. They said the additional withdrawals will instead leave it at $6.2 billion by that date.

In his letter to Lynch, Ryan said the 1912 law specifically authorizes the attorney general to sue "to enforce the provisions'' of the Enabling Act, including "the application and disposition of the said (trust) lands and the products thereof and the funds derived therefrom.''

Ducey aide Scarpinato said there's something else: The money already is flowing.