During James Monroe's presidency, the Supreme Court expanded the power of the federal government primarily through decisions that reinforced federal authority over states. The most relevant of the options provided is: It gave the federal government power to regulate the economy.
A key case during this period was McCulloch v. Maryland (1819), where the Court upheld the federal government's authority to establish a national bank and ruled that states could not tax federal institutions. This case underscored the principle of federal supremacy over state laws, thus enhancing federal power in economic matters.