Final answer:
A city ordinance may attempt to regulate actions of a federal agency, but its effectiveness may be limited by federal supremacy.
Step-by-step explanation:
A city ordinance may attempt to regulate actions of a federal agency, but its effectiveness may be limited by the principle of federal supremacy. According to the Supremacy Clause of the United States Constitution, federal law takes precedence over conflicting state or local laws. This means that if a city ordinance attempts to regulate actions that are within the exclusive jurisdiction of a federal agency, the ordinance may be invalidated.
For example, if a city passes an ordinance that attempts to regulate the activities of the Federal Bureau of Investigation (FBI), the ordinance is likely to be struck down as unconstitutional. The FBI is a federal agency and its activities are governed by federal law.
Although city ordinances may have some scope to regulate certain aspects of federal agency actions, they cannot directly conflict with federal law or impede the functioning of the federal agency.