The tariffs could also protect nascent American manufacturing by increasing the cost of imported goods, many of which came from Britain. Each region sought favorable terms for the duties on various goods. There were also questions raised about the constitutionality of these proposals, and opponents such as Jefferson feared that Hamilton's expansive interpretation of the Necessary and Proper Clause would grant Congress the power to legislate on any subject.In 1792, with their relationship completely ruptured, Jefferson unsuccessfully tried to convince Washington to remove Hamilton, but Washington largely supported Hamilton's ideas, believing that they had led to social and economic stability. Congress passed two acts related to slavery during the Washington administration: the Fugitive Slave Act of 1793, which made it a federal crime to assist an escaping slave, and established the legal system by which escaped slaves would be returned to their masters; and the Slave Trade Act of 1794, which limited the United States' involvement in the transportation of slaves by prohibiting the export of slaves from the country.