Bancroft has laid none too great stress on the influence of the English mercantile system in forcing the American Revolution, and on the attitude of the Revolution as an organized revolt against the English system.  One of the first steps by which the Continental Congress asserted its claim to independent national action was the throwing open of American ports to the commerce of all nations—­that is, to free trade.  It should, however, be added that the extreme breadth of this liberality was due to the inability of Congress to impose any duties on imports; it had a choice only between absolute prohibition and absolute free trade, and it chose the latter.  The States were not so limited.  Both under the revolutionary Congress and under the Confederation they retained the entire duty power, and they showed no fondness for free trade.  Commerce in general was light, and tariff receipts, even in the commercial States, were of no great importance; but, wherever it was possible, commercial regulations were framed in disregard of the free-trade principle.  In order to retain the trade in firewood and vegetables within her own borders, New York, in 1787, even laid prohibitory duties on Connecticut and New Jersey boats; and retaliatory measures were begun by the two States attacked.

The Constitution gave to Congress, and forbade to the States, the power to regulate commerce.  As soon as the Constitution came to be put into operation, the manner and objects of the regulation of commerce by Congress became a public question.  Many other considerations were complicated with it.  It was necessary for the United States to obtain a revenue, and this could most easily be done by a tariff of duties on imports.  It was necessary for the Federalist majority to consider the party interests both in the agricultural States, which would object to protective duties, and in the States which demanded them.  But the highest consideration in the mind of Hamilton and the most influential leaders of the party seems to have been the maintenance of the Union.  The repulsive force of the States toward one another was still sufficiently strong to be an element of constant and recognized danger to the Union.  One method of overcoming it, as a part of the whole Hamiltonian policy, was to foster the growth of manufactures as an interest entirely independent of State lines and dependent on the national government, which would throw its whole influence for the maintenance of the Union.  This feeling runs through the speeches even of Madison, who prefaced his remarks by a declaration in favor of “a trade as free as the policy of nations would allow.”  Protection, therefore, began in the United States as an instrument of national unity, without regard to national profit; and the argument in its favor would have been quite as strong as ever to the mind of a legislator who accepted every deduction as to the economic disadvantages of protection.  Arguments for its economic advantages are not wanting;