## Facts

- Federal statutes authorized mineral leasing of certain Indian lands under an 1891 Act, later amended in 1924.
- The 1924 amendment stated that production of minerals on “such lands” could be taxed by the State where the lands are located.
- Congress enacted the Indian Mineral Leasing Act of 1938 to create uniform rules for Indian mineral leasing; it authorized leasing but contained no express authorization for state taxation and included a general repealer for inconsistent prior laws.
- The Blackfeet Tribe leased oil and gas rights on its Montana reservation to non-Indian lessees under leases issued pursuant to the 1938 Act.
- Montana imposed state taxes on the Tribe’s royalty interests (the Tribe’s royalty income) derived from those leases.
- The Tribe sued in federal court seeking declaratory and injunctive relief against application of the taxes to its royalty interests.

## Issues

1. Whether Congress authorized Montana to tax the Blackfeet Tribe’s royalty interests from oil and gas leases issued under the Indian Mineral Leasing Act of 1938.
2. Whether the 1924 statute’s taxation language extends to leases issued under the separate leasing regime established by the 1938 Act.
3. Whether the 1938 Act’s general repealer clause preserves or incorporates earlier statutory authority for state taxation sufficient to satisfy the clear-consent requirement.

## Decision

- The Supreme Court affirmed the judgment for the Tribe.
- The Court held that Montana lacked authority to tax the Tribe’s royalty interests arising from leases issued under the 1938 Act.
- The Court concluded the 1938 Act contains no clear congressional consent to state taxation of tribal royalty income.
- The Court read the 1924 taxation clause as limited to lands leased under the 1891/1924 statutory framework, not leases issued under the 1938 Act.
- The Court held that a general repealer clause cannot be treated as incorporating consistent earlier provisions and, in any event, does not constitute clear congressional consent to state taxation.

## Legal Principles

- States may tax Indians only when Congress has clearly manifested consent to such taxation.
- Federal statutes affecting Indians are construed liberally in favor of Indians, and ambiguities are resolved to their benefit.
- Absent explicit statutory authorization, state taxes on tribal interests (including tribal royalty income) are invalid.
- A general repealer clause does not supply the clear statement needed to authorize state taxation of Indians.

## Conclusion

Montana could not impose state taxes on the Blackfeet Tribe’s royalty interests from oil and gas leases issued under the Indian Mineral Leasing Act of 1938 because Congress did not clearly authorize such taxation, and statutory ambiguities were resolved in favor of the Tribe.


Montana v. Blackfeet Tribe of Indians, 471 U.S. 759 (1985)