At the time of America's civil war, America as a nation was already clearly on the rise, its GDP was in comparison to all the other European nations, second only to the United Kingdom, and because of America's railroads, shipping, industrial revolution, natural resources, ingenuity, and industrious peoples, there was little doubt that America would soon surpass the relatively small island-state of the United Kingdom.
This would seem to imply that when the confederate States declared war against the Federal Union, that Europe probably was, no doubt, piqued about the possibility of exploiting such a revolution for its own benefit. However, the confederacy made a fatal error within their constitution and their raison d'être by setting their foundation for independence as a proposed separate nation entitled to their own destiny by making their cornerstone of such a revolution, the eternal institution of slavery. This sort of fundamental error, could have probably been avoided, if the confederacy rather than jumping the gun and seceding from the Union, had first made informal inquiries of their desires to European powers in a manner in which an accommodation or acquiescence of some sort of modified form of slavery could have possibly been made, that would have kept that peculiar institution viable, without upsetting European powers or southern plantation owners, especially in consideration that the United Kingdom, was the nation that led the crusade to abolish slavery in not only England but in all of its British empire.
The above did not preclude, that other countries, such as France, could not back the confederacy cause, or even the United Kingdom, for wars and politics do often make rather strange bedfellows, but this was mitigated by the fact at the time of America's civil war, that the modern world was still young, and there were therefore other countries and territories for the European powers yet to exploit, conquer, or control, without getting involved with a nation, that was an ocean away, and capable of exacting a rather high price of revenge at some future juncture. Rather, the better part of valor, was to let both sides in the America civil war to go at it, and perhaps at the conclusion of such a war, America in its weakened state, might have to turn to European banks and European ingenuity for loans, aid, and such, thereby creating a rather easy path for profit and foreign ownership of the means of a renewed American production, thus siphoning wealth off of the productivity of the American people.
Still, the south did mightily try to get the European powers on their side, and meanwhile the Union did make some diplomatic blunders, in addition to their failure to win many battles at the onset of the war, so that European nations were tempted to intervene, in one way or another, but Lincoln's cabinet was incredibly strong, silky smooth, and brilliant, especially in its acumen in handling European sensitivities and their arrogance in just the right way, so that Europe ultimately did not intervene.
In the end, the southern rebellion was put down, and this country was re-united, free of any foreign entanglements and in control of its own destiny, in addition, to becoming a stronger nation more in tune and in harmony with its declaratory creed that "all men are created equal", signifying a new birth of freedom for all.