Written by attorneys · grounded in primary & secondary sources — see below
State legislation that discriminates against interstate commerce to favor local economic interests over out-of-state competitors. Such measures trigger a virtually per se rule of invalidity under the dormant Commerce Clause unless the state demonstrates that no reasonable nondiscriminatory alternatives exist.
Sources & Authorities
How it applies
Common Examples
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Baitfish Export Ban
Elite Dynamics, an in-state hatchery, receives an order from an out-of-state buyer for live baitfish. State officials enforce an export prohibition that reserves all stock for local purchasers. The buyer sues, and the court invalidates the ban because it blocks interstate sales solely to shield in-state interests from competition.
Winery Direct-Shipment Rule
Eastern Electric, an out-of-state winery, seeks to ship wine directly to consumers in the state. The state permits only in-state wineries to make such shipments. The winery challenges the restriction, and the court strikes it down as discriminatory protectionism not saved by the Twenty-First Amendment.
Select any source to read its text and confirm it supports the definition.
Cases
Casebooks
Study Supplements
Elysium Media operates a private recycling plant outside the state. A city ordinance requires all local construction debris to go to a municipally owned recovery center. The company sues, but the court upholds the rule because it favors a public provider performing a traditional government function rather than private competitors.
Out-of-State Waste Import Ban
Emily Ellis runs a landfill in a neighboring state that accepts waste from the defendant state. The state enacts a statute blocking all out-of-state waste shipments. Ellis sues, and the court invalidates the law as simple economic protectionism that overtly blocks interstate commerce at the border.
City of Philadelphia v. New Jersey437 U.S. 617, 98 S. Ct. 2531, 57 L. Ed. 2d 475 (1978)
State Cement Sales Preference
Eugene Ellsworth owns a construction firm in a neighboring state that needs cement during a shortage. The state cement plant fills all in-state orders first and turns away out-of-state buyers. Ellsworth sues, and the court upholds the preference because the state is acting as a market participant rather than a regulator.
Reeves, Inc. v. William Stake447 U.S. 429 (1980)
Residency Requirement for Bar Admission
Esther Eisenberg, a licensed attorney living across the state line, applies for admission to the state bar. The state supreme court denies the application solely because she is not a resident. Eisenberg sues, and the court invalidates the rule as economic protectionism that the Privileges and Immunities Clause forbids.
Supreme Court of New Hampshire v. Kathryn A. Piper470 U.S. 274 (1985)
Common questions
Frequently Asked
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What distinguishes permissible conservation measures from impermissible economic protectionism?+
A state may adopt evenhanded quotas or license limits that apply equally to in-state and out-of-state users. An outright export ban that reserves a local resource exclusively for in-state buyers is protectionism and virtually per se invalid.
Does the market-participant doctrine shield all state favoritism?+
No. The doctrine permits a state to favor its own citizens when buying or selling as a market participant. It does not allow downstream conditions that regulate post-sale activity or rules that function as regulation rather than proprietary action.
When does a flow-control ordinance receive lenient review?+
A flow-control ordinance directing waste to a government-owned facility performing a traditional public function receives lenient review. The favoritism is presumed to reflect legitimate public objectives rather than simple economic protectionism.
437 U.S. 617, 98 S. Ct. 2531, 57 L. Ed. 2d 475 (1978)Constitutional Law
…commerce may be unavoidable when a State legislates to safeguard the health and safety of its people. Thus, where simple economic protectionism is effected by state legislation, a virtually per se rule of invalidity has been erected. See, e. g. , H. P. Hood & Sons, Inc. v. Du Mond, supra ; Toomer v. Witsell , 334 U. S. 385,…