CONSTITUTIONAL LAW--IMPORT-EXPORT CLAUSE--VALIDITY OF A STATE GROSS RECEIPTS TAX ON COMMON CARRIERS TRANSPORTING IMPORTS AND EXPORTS

The State of Maryland levied a nondiscriminatory gross receipts tax on revenues of common carriers operating within the state, apportioned on the basis of trackage within Maryland to trackage everywhere. Petitioners, who are common carriers operating within Maryland, objected to this tax to the extent that it constituted a tax on gross receipts derived from transporting imports and exports on the grounds that it violated the import-export clause. The court of appeals of Maryland declared the tax valid. On appeal, held, affirmed. Where the tax is on an activity connected with the import or export of goods, rather than on the goods themselves, the constitutional immunity stops at the water\u27s edge. Canton Railroad Co. v. Rogan, 340 U.S. 511, 71 S.Ct. 447 (1951); Western Maryland Railway Co. v. Rogan, 340 U.S. 520, 71 S.Ct. 450 (1951)