Was Robert yates a federalists

No, Robert Yates was not a Federalist; he was actually an Anti-Federalist. Yates opposed the ratification of the U.S. Constitution, fearing it would create a strong central government that could threaten individual liberties and the rights of states. He is best known for his writings under the pseudonym "Brutus," where he articulated his concerns about the potential dangers of a powerful federal government.