This covered not only cargo, but the vessel as well, and its effect would have been to exclude from belligerent operations non-contraband enemy's goods under the enemy's flag, if goods and ship were privately owned.
Maritime warfare on the high seas would have been limited to battles between governmentally operated war-ships.

Unless this rule were adopted also, Secretary Marcy declared that "the United States could not forgo the right to send out privateers, which in the past had proved her most effective maritime weapon in time of war, and which, since she had no large navy, were essential to her fighting power." "War on private property," said the Americans, "had been abolished on land; why should it not be abolished also on the sea ?" The American proposal met with general support among the smaller maritime nations.

It was believed that the one great obstacle to the adoption of Marcy's amendment lay in the naval supremacy of Great Britain, and that obstacle proved insurmountable.

Thus the United States refused to accede to the Declaration, and there the matter rested until 1861.

But on April 17 Jefferson Davis proclaimed for the Southern Confederacy the issue of privateers against Northern commerce.