Several states have explicit provisions guaranteeing the right to vote in their constitutions. Here are some examples:
California: Article II, Section 2 of the California Constitution explicitly states: "A United States citizen 18 years of age and resident in this State may vote."
Florida: Article VI, Section 2 of the Florida Constitution affirms: "Every citizen of the United States who is at least eighteen years of age and who is a permanent resident of the state, if registered as provided by law, shall be an elector of the county where registered."
New York: Article II, Section 1 of the New York Constitution declares: "Every citizen shall be entitled to vote at every election for all officers elected by the people and upon all questions submitted to the vote of the people provided that such citizen is eighteen years of age or over and shall have been a resident of this state, and of the county, city, or village for thirty days next preceding an election."
Texas: Article VI, Section 2 of the Texas Constitution states: "Every citizen shall be a qualified elector of this state unless he is a person with mental incapacity or a felon, or has been convicted of a felony under this State or federal law or law of another state which, if the person were convicted in this State, would be a felony under the laws of this State."
These are just a few examples. Other states may have similar explicit provisions in their constitutions guaranteeing the right to vote.