The Senate hearings considering Elena Kagan’s Supreme Court nomination called new attention to the Constitution's Commerce Clause. That concern might seem odd, given the typical lack of strong grassroots concern over the commerce power. But the 2010 election year is different. One characteristic of the largely conservative "Tea Party" movement is a wish to roll back Constitutional time to the regime envisioned by its founders. As the New York Times reported in early July, 2010, members of the movement believe that the “commerce clause in particular has been pushed beyond recognition.” Members of the movement imagine that Congressional power over "commerce among the states" strictly requires two things. First, the action must relate to commercial exchange. Second, the transaction must be "interstate," involving participants or activities that actually cross a state line.
The first of these views must be qualified and the second is incorrect. In the late eighteenth century the word "commerce" frequently had a broader meaning than mere trade. The framers' own repeated use of the phrase "trade or commerce" indicated that "trade" and "commerce" were different things and could include both manufacturing and even “mutual dealings in common life,” as Webster put it in his 1828 American Dictionary.
The phrase commerce "among” the several states was certainly not intended to be limited to transactions that crossed a state line. If the framers had so intended they would have used the word "between" as they did in the diversity jurisdiction clause, where they contemplated legal process flowing from a plaintiff in one state to a defendant in a different state. Eighteenth century writers distinguished the terms "between" and "among" much more carefully than we do today. Commerce "among" the states had the same meaning as John Dickinson's Letters From a Farmer arguing for repeal of export duties on goods made in the colonies, “for so doing may promote manufactures among them." Or an 1800 writer in the Hartford Connecticut Courant could write that the states of Pennsylvania and New York "have many men of intrigue and talents among them." And New York Convention delegate Robert Yates could speak of the Articles of Confederation as intended "to preserve peace among the states." When the framers wanted to speak about a transaction or event that crossed from state A to state B they used "between." When they wanted to speak of an activity or state of affairs generally occurring within a certain area or areas they used "among."
Hovenkamp, Herbert J., "Judicial Restraint and Constitutional Federalism: The Supreme Court's Lopez and Seminole Tribe Decisions" (1996). Faculty Scholarship at Penn Law. 1941.