← The hardest concepts in United States law
In one breath
Even when Congress has said nothing, the Commerce Clause is read to stop states from discriminating against interstate commerce or burdening it far beyond their local benefit. A state law that favors local interests at the expense of outsiders is close to automatically invalid, while an even-handed law is balanced against its burden.
The picture
The apartment building’s shared hallway
In an apartment building each tenant may furnish their own apartment as they like. The shared hallway is different, because everyone needs it to get in and out. A tenant may not block the hallway, or charge visiting delivery people a fee that residents of the building do not pay, even if the building manager has never written a rule on the point. The manager (Congress) holds the power to regulate the hallway, but while the manager is silent the janitor (the courts) still enforces the idea that no tenant may hoard it.
The janitor looks for two things. One is favoritism: a rule that treats outsiders worse than residents, such as a fee only for deliveries from other buildings, is nearly always struck down. The other is excessive burden: a rule that applies to everyone alike but makes passage so hard that it costs far more than the tenant gains is weighed and may be struck down. The manager can at any time write a rule that overrides the janitor’s, even one that allows the favoritism.
Where the picture stops working
In the building the janitor’s authority is written down. In constitutional law the doctrine is an inference from the Commerce Clause’s grant of power to Congress, and some Justices have doubted it. The picture also leaves out the market-participant exception: when a state itself buys or sells goods, the limits generally do not apply.
How it really works
- 1Ask whether Congress has regulated the area. If a federal statute applies, the question becomes one of preemption. Congress can also expressly authorize state laws that the doctrine would otherwise forbid.
- 2Ask whether the state law discriminates against interstate commerce, on its face, in purpose or in practical effect, by favoring in-state economic interests over out-of-state ones.
- 3If it does, the law is treated as virtually invalid. It survives only if the state shows that it serves a legitimate local purpose that no reasonable non-discriminatory alternative could serve.
- 4If the law is even-handed, apply the balancing test: it is valid if it serves a legitimate local purpose and the burden on interstate commerce is not clearly excessive in relation to the local benefits (Pike v. Bruce Church).
- 5Check the exceptions, above all the market-participant exception, and whether Congress consented.
Why people get it wrong
- Thinking the Commerce Clause only grants power to Congress. The dormant doctrine is its negative implication.
- Believing every burden on interstate trade is forbidden. Only discrimination or a clearly excessive burden is.
- Looking only at the text. Discrimination can lie in the law’s purpose or its practical effect.
- Assuming a good local purpose saves a discriminatory law. It must usually be pursued by non-discriminatory means.
- Confusing it with preemption. The dormant doctrine works when Congress is silent, preemption when Congress has spoken.
A worked example
The facts are invented
The invented state of Fenn passes two laws. The first bans the sale of out-of-state eggs unless inspected in Fenn by inspectors who charge a fee, while Fenn eggs are exempt. The law treats outsiders worse on its face, so it is close to automatically invalid. Fenn would have to show that no reasonable alternative, such as accepting another state’s inspection, could protect public health, and that is difficult.
The second requires every truck on Fenn’s roads to have rear mud flaps of a particular shape that no other state permits. It applies to everyone alike, so the court balances. Fenn’s safety gain appears slight, while trucks passing through must change equipment at its border or take long detours. If the burden is clearly excessive in relation to the benefit, the law fails even though it discriminates against no one.
Try it
State S taxes grain sold in S at a lower rate when it was grown by S farmers than when it was grown elsewhere. S says its aim is simply to raise revenue. What is the best analysis?
Landmark authorities
Read the sources themselves; this list is a starting point.
- Gibbons v. Ogden, 22 U.S. (9 Wheat.) 1 (1824)
- Bibb v. Navajo Freight Lines, Inc., 359 U.S. 520 (1959)
- Pike v. Bruce Church, Inc., 397 U.S. 137 (1970)
- City of Philadelphia v. New Jersey, 437 U.S. 617 (1978)
Where to go next
More hard concepts in United States law
- Standing, ripeness and mootness (Constitutional law)
- The levels of scrutiny in equal protection (Constitutional law)
- Federal preemption (Constitutional law)
- The Eleventh Amendment and state sovereign immunity (Constitutional law)
This page is an educational overview. It is not legal advice and not a substitute for the sources: the statute, the rule, the case itself. United States law is made in fifty states and in the federal system, and the rules differ between them. Each page states the usual formulation of the rule and names landmark decisions; your own state, circuit or course may use different wording. Check the primary sources before relying on any rule.