The USEPA's ability to enforce the Clean Air Act $($CAA$)$ has changed since its inception; the breadth of the CAA has been both augmented and restricted in recent years. In your answer, thoroughly describe how each of the following four elements of the policymaking process might affect the status of the Clean Air Act: $(1)$ US Congress, $(2)$ POTUS, $(3)$ SCOTUS, and $(4)$ Federal vs$.$ States rights $($i$.$e$.,$ federalism$).$ In your answer, make sure to reference examples of how each of the four elements has influenced the status of the CAA.