Also known as: fairly apportioned · apportionment
Written by attorneys · grounded in primary & secondary sources — see below
A requirement that a state tax affecting interstate commerce be allocated according to a rational formula reflecting the extent of the taxable activity or property within the taxing state. The rule prevents the same economic activity from being subjected to cumulative tax burdens by multiple states.
Faith Fitzgerald, a voter in a rural county, sued state officials after a new legislative map placed her district across three counties to favor urban interests. The complaint alleged that the map diluted rural votes without any manageable standard to justify the lines. The court denied the motion to dismiss, finding no textually demonstrable commitment of apportionment disputes to another branch and no lack of judicially discoverable standards.
Ferrum Metals and Fusion Power both discharged pollutants into a river that reached Francois Fortier's downstream farm. Ferrum paid the full damages and then sought contribution from Fusion. Fusion failed to prove any reasonable basis for dividing the indivisible harm, so the court held Fusion jointly and severally liable for the entire amount.
Select any source to read its text and confirm it supports the definition.
Farah Fox subdivided her ranch into three parcels and sold two to separate buyers. Summit Pipeline held an easement across all three parcels. The court apportioned the easement's transmission capacity among the parcels to prevent an unreasonable increase in the burden on the servient land.
Farid Farahani and Floyd Franklin sought dissolution after twenty years of marriage. The court equitably apportioned their combined assets, including retirement accounts and the family home, after weighing each spouse's contributions, needs, and future earning capacity without regard to fault.
Felix Franco sued two factories whose emissions combined to damage his orchard. The evidence showed distinct periods of exposure but a single crop loss. The court determined that the harm was capable of apportionment and instructed the jury on allocation rather than leaving the question entirely to the jury.
Frostline Textiles subdivided its industrial site into four lots and sold three. A recorded covenant required maintenance of a shared drainage system. The court held that each new owner remained subject to the covenant but apportioned the maintenance costs among the parcels to avoid an unreasonable increase in any single owner's burden.
The fair-apportionment requirement limits a state to taxing only its rational share of the activity or property located within its borders. Without this limit the same income could be taxed multiple times by different states.
Each resulting parcel ordinarily receives the benefit of the easement or profit. A court may impose reasonable apportionment if unrestricted use by all new owners would unreasonably increase the burden on the servient estate.
Each actor seeking to limit liability must prove that the harm is capable of apportionment and must establish a reasonable basis for the division. The plaintiff does not bear this burden once joint causation is shown.
The court considers the duration of the marriage, each spouse's contributions to acquisition and preservation of assets, age, health, occupation, income, needs, and opportunities for future acquisition of capital, among other statutory factors.
…the Constitution: in the listing of qualifications for Representatives and Senators, Art. I, § 2, cl. 2, and § 3, cl. 3; in the Apportionment Clause, Art. I, § 2, cl. 3; in the Migration and Importation provision, Art. I, § 9, cl. 1; in the Emolument Clause, Art. I, § 9, cl. 8; in the Electors provisions, Art. II, § 1, cl. 2, and…