Final answer:
For an action by the federal government to be valid, it must have a secular purpose and not violate constitutional limitations.
Step-by-step explanation:
For an action by the federal government to be valid, it must meet two distinct requirements: it must have a secular purpose and it must not violate any constitutional limitations.
The first requirement means that the action or law must have a non-religious justification. This ensures that the government is not favoring or endorsing any particular religion.
The second requirement refers to the constitutional limitations placed on the federal government. These limitations include restrictions on the government's power, such as the prohibition of passing laws that assign guilt without court proceedings or interfere with legal contracts.