Final answer:
The federal government cannot deny citizens the right to vote because of failure to pay taxes due to the Twenty-Fourth Amendment. This amendment, ratified in 1964, outlawed the poll tax in national elections.
Step-by-step explanation:
The level of government that cannot deny citizens the right to vote because of failure to pay taxes is the federal government. According to the Twenty-Fourth Amendment of the United States Constitution, it is unconstitutional to require citizens to pay a poll tax in order to vote in national elections. This amendment, ratified in 1964, banned the practice of the poll tax in elections for federal offices.