During the fifth century, the Roman Empire began to decline intensely. Numerous problems ultimately contributed to the overthrow of the empire, whose decline has been linked to 476 AD.
The last Roman emperor was Romulus Augustus, and his crown was taken over by the barbarian warlord Odoacer. Just how powerless the ruler of Rome was at that moment is evidenced by the fact that he was retired by the Odoacer. So he did not liquidate him because he had not the slightest doubt that he could be threatened.
Marbury v. Madison set the precedent of judicial review, wherein the Supreme Court has the ability to deem a congressional bill unconstitutional. Therefore, the first clause would be your best bet.
