John G. Nicolay, The Outbreak of Rebellion

[78] ultimate reliance upon foreign intervention in their behalf “Cotton is king,” they argued; Europe cannot exist without it; therefore, when American civil war locks up that daily food of European looms, and takes the means of earning daily bread from foreign labor, dividends from foreign capital, and activity from foreign commerce, European governments must open our ports by recognizing and protecting our flag, especially if, in addition to their needed manufacturing staple, we tempt them with the commercial harvest of free trade.

As the entering wedge to this policy, Jefferson Davis, on the 17th of April, issued his proclamation, offering letters of marque and reprisal, “under the seal of these Confederate States,” to armed privateers of any nation. The commercial classes of England had, since the secession of South Carolina, manifested a strong sympathy for the rebellion, and he doubtless expected that the seas would soon swarm with predatory adventurers under shelter of the “stars and bars.” A few vessels of this character did, in the subsequent years of the war, inflict incalculable damage upon shipping sailing under the Federal flag; but the extravagant scheme, of which this privateering proclamation was the key-note, withered in an early blight. Two days after its appearance President Lincoln issued a counter-proclamation, instituting a rigid blockade of the insurgent ports, and threatening that Jefferson Davis' privateers should be “held amenable to the laws of the United States for the prevention and punishment of piracy” --a warning which, from motives of public policy and the humane personal instincts of the President, was not literally enforced. The unexampled increase of the United States Navy, the extraordinary efficiency of the blockade, the vigilant foreign diplomatic service of the administration, and, above all, its vigorous prosecution of the war,