This particular multinational European intrusion into the Western Hemisphere was a matter of seizing the opportunity of the American Civil War, when the government in Washington was temporarily distracted from enforcing its own imperial Monroe Doctrine by more pressing dangers. The US government would have resorted to another war in Mexico to remove what they rightly regarded as a French puppet regime that endangered American national interest. But the Mexican people beat them to it.
But the adventure of Maximiliano I was only one way in which the US Civil War affected European politics. Antislavery sentiment was strong in England, and whether Britain should recognize the Confederacy as an independent government was a major political issue. That controversy also involved whether the British government would move to break the Union naval blockade of the Confederacy, which would have improved the Confederacy's chances of military success. The European politics of the Civil War received considerable attention from a couple of German political exiles living in London who were later to achieve considerable international fame, Karl Marx and Frederick Engels, who published contemporary articles during the first couple of years of the war in Vienna's Die Presse and the New York Daily Tribune.
I don't recall it being emphasized in any of the Lost Cause writing that I've sifted through if it is much emphasized that the creators of Marxism were supporters of the Union and the man neo-Confederates deride as a dictator and "King Lincoln." I'm sure it pops up now and then. In that, of course, the two men shared in the broad democratic opinion in Europe in sympathizing with the Union and against the slave republic in the South.
But their description of the war in Die Presse of March 26, 1862, could be taken as compatible with the continuing American conceit that our Civil War must have been the biggest, most Exceptional civil war ever:
From whatever standpoint one regards it, the American Civil War presents a spectacle without parallel in the annals of military history. The vast extent of the disputed territory; the far-flung front of the lines of operation; the numerical strength of the hostile armies, the creation of which drew barely any support from a prior organizational basis; the fabulous costs of these armies; the manner of leading them and the general tactical and strategical principles in accordance with which the war is waged, are all new in the eyes of the European onlooker. (English translation from The Civil War in the U.S. by Marx and Engels, 1961 edition)This is all presumably true in military terms. But in the scope of destruction and its political ramifications, the Thirty Years War of 1608-10648 was surely more consequential in Europe. And, sadly, the world has seen many civil wars since 1865.
But there were significant implications for the future of Europe, especially for the future of democracy, in the outcome of the Civil War. David Brion Davis, a major historian of US slavery, The Terrible Cost of Reconciliation New York Review of Books 07/18/2002:
... a Confederate victory would have created an enormous impediment to the growth of democracy in Britain. This conclusion, underscored by the political and class alignments in Britain, conforms with the grim speculations of the economic historian and Nobel Laureate Robert William Fogel. After briefly surveying the plight of most workers in Europe and even England in the 1850s and 1860s, Fogel suggests that a Confederate victory would have delivered a devastating blow to antislavery and progressive politics, replacing democracy and liberal reform with “a drive for aristocratic privilege under the flags of paternalism and the preservation of order.”Fogel co-authored one of the more embarrassing episodes in Civil War historiography, one which exaggerated the productivity of slavery via a poor analysis of econometric data. The question of the productivity of slave labor is an empirical one. But it also has figure heavily in polemical historical arguments over the years.
Given the high productivity of slave labor, an independent Confederacy could have exploited its monopoly on cotton by passing on a small sales tax to consumers, a tax that would have financed a huge standing army, along with expansionist, proslavery policies that might well have led to Confederate domination of Latin America and a reversal of Britain’s antislavery pressures on Cuba and Brazil. While Fogel is fully aware that the abolition of American slavery brought “no heaven on earth,” there is much to be said for his argument that Confederate independence would have greatly increased the power of the most conservative movements in much of the world. [my emphasis]
In an earlier article, Davis wrote (The Benefit of Slavery New York Review of Books 03/31/1988):
Historians have only begun to free themselves from the antislavery assumptions that permeated conceptions of political economy from the time of Benjamin Franklin and Adam Smith. We still find it difficult to believe that a flagrantly unjust system of labor could be compatible with long-term economic and material progress. But despite the many valid criticisms directed against Robert William Fogel and Stanley L. Engerman’s Time on the Cross (1974), more recent research has confirmed their contention that slave labor could be efficient, productive, and adaptable to a variety of trades and occupations ranging from mining and factory work to the technologically modernized Cuban sugar mills. Indeed, in Cuba and Brazil as well as in the southern United States slavery continued to flourish until governments moved after 1860 to abolish it.But in that same article, Davis also cautions about the need to be careful into falling into traps set by polemical arguments over slave productivity from even before the Civil War.
In the 2002 article, he points to an historical interpretation that greatly influenced British controversies over the US Civil War:
The initial caution and passivity of British abolitionists may well have been related to a subject that has been neglected or underestimated by historians: the drastic “failure” of West Indian slave emancipation. I use quotation marks to suggest that the disappointment and embarrassment did not concern the happiness and well-being of blacks but rather the expectations of whites, including many abolitionists, who often assumed that freed slaves would work harder and more efficiently on colonial plantations. However, wherever freedpeople could find plots of land for subsistence agriculture, they fled the plantations or worked as little as possible. After the end of so-called apprenticeship in 1838, both Britain and the Southern states absorbed a stream of evidence showing that freed blacks did everything they could to escape slave-like gang labor, and that plantation production and land values had plummeted. The evidence showed moreover that Britain had desperately turned to India and other poverty-stricken regions to find thousands of indentured laborers who could be transported to the West Indies, and that Cuba and Brazil, which still imported large numbers of slaves from Africa, had greatly prospered, especially in producing sugar and coffee for the world’s expanding markets.And he describes the state of British public opinion as the war proceeded, mentioning the role played by another Andrew Jackson:
As Thomas Carlyle summed up the matter in his essay “Occasional Discourse on the Nigger Question,” published in 1849, the freed slaves had simply refused to work and the economies of the West Indies had collapsed. Lord Wolseley, Blackett tells us, “was convinced that West Indian emancipation had been ‘a failure in every respect.'” Anthony Trollope and numerous others conveyed the same message of Negroes “squatting” in idleness, an image confirmed by even a former Chartist, Joseph Barker, who became “one of the Confederacy’s most active proponents” after returning from a residence in the United States.
During the first part of the war, most Britons thought that the North had no chance of victory; even the able American ambassador Charles Francis Adams concluded that it was only a matter of time before Britain recognized the Confederacy. Yet defenders of the Union took it as their task to convince the British government to continue on its course of neutrality, and to persuade most of the working and middle classes that a united, democratic America was a symbol of hope for all people favoring political reform as well as a place of refuge for the world’s oppressed. These were the arguments of John Bright, the liberal manufacturer and MP from Birmingham, who helped to overcome the appeal of Confederate agents like the Swiss-born Henry Hotze, who published many articles in the press. Bright’s campaign gained much ground when working-class leaders organized and financed a huge meeting of the Union and Emancipation Society in Manchester’s Free Trade Hall a day before Lincoln’s Emancipation Proclamation took effect.
While Lincoln’s actions undermined those abolitionists who contended that slaves would have a better chance of freedom in an independent Confederacy, a large cadre of African-American speakers, including J. Sella Martin, William and Ellen Craft, and Henry “Box” Brown, challenged racist stereotypes and kept reminding Britons that slavery stood at the center of the American war. Nothing could embody this point more forcefully than the speeches of William Andrew Jackson, the escaped slave and former coachman of the Confederacy’s President Jefferson Davis.
Blackett observes that the British public was surprisingly well informed about America; the frequent meetings and rallies concerning the Civil War were not spontaneous but carefully planned and organized. Even so, there was much heckling and disruption, as when pro-Union groups would join in singing “John Brown’s Body” to drown out pro-Confederate speeches. Though pro-Confederate agents succeeded in organizing many unemployed workers in Lancashire, this was not the case in the cotton towns of Scotland and Ireland. A larger than expected number of millowners supported the Union cause, as did an increasingly wider cross section of businessmen and manufacturers. Thus despite the large number of pro-Confederate newspapers, [R.J.M.] Blackett documents an overwhelming public enthusiasm for the Union during the last years of the war, culminating in widespread acclaim, grief, and huge funeral processions following the assassination of Lincoln, whose portrait would long be a common fixture in British artisan homes. [my emphasis]