As you may know, in his somewhat wacky April 1, 1861 "April Fools Memorandum", entitled Some Thoughts for the President's Consideration, Secretary of State William H. Seward recommended to President Abraham Lincoln, among other things, that the United States declare war on Spain and France:
I would demand explanations from Spain and France, categorically, at once.
I would seek explanations from Great Britain and Russia, and send agents into Canada, Mexico, and Central America to rouse a vigorous continental spirit of independence on this continent against European intervention.
And, if satisfactory explanations are not received from Spain and France,
Would convene Congress and declare war against them.
In her beautifully written book, A World on Fire: Britain's Crucial Role in the American Civil War, Amanda Foreman provides evidence that Seward had been contemplating the possibility of war as a means of diverting secession for almost two months before he delivered his memorandum to Lincoln. On the morning of February 3, 1861, "Seward paid a surprise call on Lord Lyons," the British envoy to the United States in Washington. In a confidential memorandum to his government, Lord Lyons reported that, during the meeting, Seward indicated that a foreign war would not displease him. Lyons reported that
Seward also repeated to him a recent conversation with the minister from Bremen (one of the smaller states of the German Confederation), "no doubt for my instruction." The hapless diplomat had complained about the Republican Party's election promise to place tariffs on foreign imports, saying that such a move would turn Europe against America at the moment when she most needed friends. Seward claimed to have replied that nothing would give him more pleasure, since he would then have the perfect excuse for an international quarrel, "and South Carolina and the seceding states would soon join in."