Way to beat me to it. While we're on the subject, the Founding Fathers learned well from the fall of the Roman Republic.
Even in the heyday of the Republic, Rome had a convention of suspending civil government when the city was threatened, in favour of a temporary dictator. Cincinnatus was one of those dictators. That convention was the hook that Caesar Augustus used to establish the Empire. He clothed himself in the tradition of the temporary dictators - only in his case, it was permanent.
The United States has no such loophole. Even during the Civil War, when the U.S. government was at its most tyrannical with respect to civil liberties, elections were still held on schedule. President Lincoln had to run for re-election in 1864. As confirmed by World War 2, even total war is no reason to suspend or even postpone elections. Americans have always had the right to change CinCs in mid-war, and still do.
Consequently, there's no customary loophole for a would-be Emperor to exploit. America may degenerate into a dictatorship, but it surely would be an elective dictatorship. Sadly, the continuance of elections would make such dictators claim loudly that they aren't really tyrants.
When Octavian, Marc Antony, and Lepidus joined forces in late 43 B.C., they created the Triumvirate which was in effect a three-man dictatorship, but they avoided the term "dictator." Eventually Octavian had sole control but in fashioning a legal basis for his authority after 31 B.C., he avoided the term "dictator." He had learned from his uncle's mistakes.