INTRODUCTION

The question of preemption arises because the Constitution establishes a federal system with two governments (one federal and one state) that have overlapping power to regulate the same matters involving the same parties in the same territory. To succeed, such a system requires a means of deciding when federal law displaces state law. The Founders chose the Supremacy Clause (reinforced by Article III) to perform this function. Although seemingly one-sided, the Clause actually incorporates several important political and procedural safeguards designed to preserve the proper balance between the governance prerogatives of the federal government and the states. It does this by recognizing only three sources of law as “the supreme Law of the Land”: the “Constitution,” “Laws,” and “Treaties” of the United States. Elsewhere, the Constitution prescribes precise and cumbersome procedures to govern the adoption of each source of supreme federal law. These procedures establish the exclusive means of adopting “the supreme Law of the Land.” By requiring the participation and assent of multiple actors subject to the political safeguards of federalism, these procedures make supreme federal law relatively difficult to adopt. More importantly, these procedures suggest exclusivity because the Constitution guarantees states (regardless of size or population) equal suffrage in the Senate and gives the Senate (or the states) an absolute veto over the adoption of each and every source of law recognized by the Supremacy Clause.