Marx wrote in the Introduction to _Capital_ that the US Civil War was as important to the working class as the American colonial war for independence had been for the bourgeois class...
In 1869, the 1st International General Council approved Marx's resolution calling for the National Labor Union in the US to oppose war with Europe...Marx's resolution reminded US workers that the International's congratulatory letter to Lincoln following his re-election asserted that the civil war would advance working class interests as the earlier war for independence had advanced bourgeois class interests..
Marx argues that the abolition of slavery signalled a new era in the working class movement, one characterized by growing working class independence in the US and growing international working class cooperation...he points out that the old parties and establishment politicians look askance at these developments and he indicates that they will to go to war to crush them...according to Marx, only years of peace would further working class interests, internecine war, on the other hand, would be in the general interests of the common oppressors of the working class...
Marx's resolution (written in English) also notes that an immediate effect of the US civil war was a huge national debt, the burden of which was imposed on working people by 'financial aristocrats' and similar 'vermin' (when questioned about the appropriateness of the word vermin, M replied that there was no other word to describe them)... Michael Hoover