lines constitute "Commerce among the several States" so as to make them subject to regulation by Congress under the Commerce Clause? Since it is our conclusion that the Sherman Act was intended to apply to the fire insurance business we shall, for convenience of discussion, first consider the latter question.
Ordinarily courts do not construe words used in the Constitution so as to give them a meaning more narrow than one which they had in the common parlance of the times in which the Constitution was written. To hold that the word commerce" as used in the Commerce Clause does not include a business such as insurance would do just that. Whatever other meanings "commerce" may have included in 1787, the dictionaries, encyclopedias, and other books of the period show that it included trade: business in which persons bought and sold, bargained and contracted. And this meaning has persisted to modern times. Surely, therefore, a heavy burden is on him who asserts that the plenary power which the Commerce Clause grants to Congress to regulate "Commerce among the several States" does not include the power to regulate trading in insurance to the same extent that it includes power to regulate other trades or businesses conducted across state lines. . . .
A large share of the insurance business is concentrated in a comparatively few companies located, for the most part, in the financial centers of the East. Premiums collected from policyholders in every part of the United States flow into these companies for investment. As policies become payable, checks and drafts flow back to the many states where the policyholders reside. The result is a continuous and indivisible stream of intercourse among the states composed of collections of premiums, payments of policy obligations, and the countless documents and communications which are essential to the negotiation and execution of policy contracts. Individual policyholders living in many different states who own policies in a single company have their separate interests blended in one assembled fund of assets upon which all are equally dependent for payment of their policies. The decisions which that company makes at its home office -- the risks it insures, the premiums it charges, the investments it makes, the losses it pays -- concern not just the people of the state where the home office happens to be located. They concern people living far beyond the boundaries of that state. . . .
Despite all of this, despite the fact that most persons, speaking from common knowledge, would instantly say that of course such a business is engaged in trade and commerce, the District Court felt compelled by decisions of this Court to conclude that the insurance business can never be trade or commerce within the meaning of the Commerce Clause. We must therefore consider these decisions.
In 1869 this Court held in sustaining a statute of Virginia which regulated foreign insurance companies, that the statute did not offend the Commerce Clause because "issuing a policy of insurance is not a transaction of commerce." Paul v. Virginia, 8 Wall, 183. Since then, in similar cases, this statement has been repeated, and has been broadened. . . .
In all cases in which the Court has relied upon the proposition that "the business of insurance is not commerce," its attention was focused on the validity of state statutes -- the extent to which the Commerce Clause automatically deprived states of the power to regulate the insurance business. Since Congress has at no time attempted to control the insurance business, invalidation of the state statutes would practically have