Carrington v. Rash
In Carrington v. Rash, 380 U.S. 89 (1965), the U.S. Supreme Court invalidated a Texas law that prohibited "any member of the Armed Forces of the United States" who moves his home to Texas during the course of his military duty from ever voting in any election in that State "so long as he or she is a member of the Armed Forces."
The Court did state, in a passage often quoted, that States "have broad powers to determine the conditions under which the right of suffrage may be exercised."
- 380 U.S. at 91 (quoting Lassiter v. Northampton County Bd. of Elections, 360 U.S. 45, 50 (1959)).