This is a cartoon depicting the state line between Texas, where one person gets one vote, and New Mexico, where one person supposedly gets two votes. This is a play on the fact that the President is elected by the electoral college, a body comprised of the same number of electors as there are Representatives and Senators from a state; meaning the vote cast by someone in a state like Texas with a large population compared to the number of Representatives and Senators, would not "count" as much as a vote cast by an individual in a state like New Mexico, with a relatively small population compared to the number of Representatives and Senators.