25 CFR 89.40: General policy.

In ordinary circumstances, legal services with respect to trust resources are provided for Indian tribe(s):

(a) By private counsel employed by tribes when such tribe is financially able and elects to do so, or

(b) By the United States as trustee through the Office of the Solicitor and/or the Department of Justice.

It is the policy of the Department of the Interior not to use federally appropriated funds to pay for private counsel to represent Indian tribes. Exceptions to that policy are listed in § 89.41 of this part.