| Litigants: | Louisiana v. United States (1965) |
| Arguedate: | January 26 |
| Argueyear: | 1965 |
| Decidedate: | March 8 |
| Decideyear: | 1965 |
| Fullname: | Louisiana et al. v. United States |
| Usvol: | 380 |
| Uspage: | 145 |
| Parallelcitations: | 85 S. Ct. 817; 13 L. Ed. 2d 709 |
| Prior: | United States v. Louisiana, 225 F. Supp. 353 (E.D. La. 1963); probable jurisdiction noted, . |
| Majority: | Black |
| Joinmajority: | Warren, Douglas, Clark, Brennan, Stewart, White, Goldberg |
| Concurrence: | Harlan |
Louisiana v. United States, 380 U.S. 145 (1965), was a case decided by the Supreme Court of the United States that dealt with an "interpretation test" permitted by the Louisiana Constitution of 1921 alleged to deprive Louisiana Negroes of voting rights in violation of 42 U.S.C. Section 1971(a) and the Fourteenth and Fifteenth Amendments.
The test gave complete discretion to registrars to deny an applicant the ability to register to vote if he could not "give a reasonable interpretation" of any clause in the Louisiana Constitution or the Constitution of the United States.