UCLA School of Law

This article introduces the concept of the depth of Congress's commerce power alongside the more familiar focus on its breadth, and argues that both are important for understanding the power's full contours. Moreover, as illustrated by a detailed comparison of the Lochner and New Deal Courts, breadth and depth may pull in opposite directions and so complicate traditional labeling of constitutional eras as favoring either state or national authority.

Thus, although the Lochner Court undoubtedly held a limited view of the breadth of the commerce power, at the same time it also held an unlimited view of the depth of that power - in the sense of the impact on state authority of its valid exercise. It conceived of the commerce power as latently exclusive of state authority, meaning that federal regulation automatically terminates state authority in the same area. The Lochner Court employed this deep conception of the commerce power to promote not the market in the abstract, but specifically the national market. Where economic union was at stake, the Lochner Court looked with favor on regulation at the national level and was keen to find that federal laws displaced state authority in situations in which later Supreme Courts would not, thereby trumping its laissez-faire and federalism commitments. The Lochner Court's twin positions of the limited breadth and unlimited depth of the commerce clause were exactly reversed during the New Deal era as part of a new federalism balance. Although the New Deal Court expanded the breadth of national powers under the commerce clause, it also reduced their depth. It did so by holding that Congress's power is no longer to be understood as latently exclusive of state authority but concurrent with it, and by introducing the modern presumption against preemption.