The people of England, of France, of Germany, of Europe, consider the cause of the United States as their own cause, as the cause of liberty, and that, despite all paid sophistry, they consider the soil of the United States as the free soil of the landless millions of Europe, as their land of promise, now to be defended sword in hand, from the sordid grasp of the slaveholder. ... All the wars waged in Europe [since 1850] have been mock wars, groundless, wanton, and carried on on false pretenses. The Russian war, and the Italian war, not to, speak of the piratical expeditions against China, Cochin-China, and so forth... The first grand war of contemporaneous history is the American war. ... In this contest the highest form of popular self-government till now realized is giving battle to the meanest and most shameless form of man’s enslaving recorded in the annals of history.There's also Marx's letter, on behalf of the International Workingmen's Association, congratulating Lincoln on his reelection:
When an oligarchy of 300,000 slaveholders dared to inscribe [the word] "slavery" on the banner of Armed Revolt, on the very spot ... whence the first Declaration of the Rights of Man was issued, and the first impulse given to the European revolution of the eighteenth century..., and maintained slavery to be "a beneficent institution", indeed, the old solution of the great problem of "the relation of capital to labor", and cynically proclaimed property in man "the cornerstone of the new edifice" — then the working classes of Europe understood at once, even before the fanatic partisanship of the upper classes for the Confederate gentry had given its dismal warning, that the slaveholders' rebellion was to sound the tocsin for a general holy crusade of property against labor, and that for the men of labor, their hopes for the future, even their past conquests were at stake in that tremendous conflict on the other side of the Atlantic...Still not quite the definitive statement I'm looking for, but closer.
The workingmen of Europe feel sure that, as the American War of Independence initiated a new era of ascendancy for the middle class, so the American Antislavery War will do for the working classes. They consider it an earnest of the epoch to come that it fell to the lot of Abraham Lincoln, the single-minded son of the working class, to lead his country through the matchless struggle for the rescue of an enchained race and the reconstruction of a social world.
His assessment of Lincoln is interesting, too:
Lincoln is a sui generis figure in the annals of history.He has no initiative, no idealistic impetus, no historical trappings. He gives his most important actions always the most commonplace form. Other people claim to be “fighting for an idea”, when it is for them a matter of square feet of land. Lincoln, even when he is motivated by, an idea, talks about “square feet”. He sings the bravura aria of his part hesitatingly, reluctantly and unwillingly, as though apologising for being compelled by circumstances “to act the lion”. The most redoubtable decrees — which will always remain remarkable historical documents -- flung by him at the enemy all look like, and are intended to look like, routine summonses sent by a lawyer... His latest proclamation, which is drafted in the same style, the manifesto abolishing slavery, is the most important document in American history since the establishment of the Union, tantamount to the tearing up of the old American Constitution.
Nothing is simpler than to show that Lincoln’s principal political actions contain much that is aesthetically repulsive, logically inadequate, farcical in form and politically, contradictory, as is done by, the English Pindars of slavery, The Times, The Saturday Review and tutti quanti. But Lincoln’s place in the history of the United States and of mankind will, nevertheless, be next to that of Washington. Nowadays, when the insignificant struts about melodramatically on this side of the Atlantic, is it of no significance at all that the significant is clothed in everyday dress in the new world?
Lincoln is not the product of a popular revolution. This plebeian, who worked his way tip from stone-breaker to Senator in Illinois, without intellectual brilliance, without a particularly outstanding character, without exceptional importance-an average person of good will, was placed at the top by the interplay of the forces of universal suffrage unaware of the great issues at stake. The new world has never achieved a greater triumph than by this demonstration that, given its political and social organisation, ordinary people of good will can accomplish feats which only heroes could accomplish in the old world!