The Battle of Diu: Hoisted from the Archives

A spectacular catch by the highly-learned Adam Tooze, from his War in Germany, 1618-2018: Lecture 9: 1848 and the Impasse of Conservative Militarism in Prussia. The question here is: is Friedrich Engels threatening that the Angel of History will bring about the cultural elimination of the Slavic peoples of Greater Austria and Greater Hungary, or the physical elimination of the Slavic peoples of Greater Austria and Greater Hungary—"demographic replacement", either via exile or genocide?:

Adam Tooze: In February 1849 Frederick Engels wrote the following truly menacing lines for the Neue Rheinische Zeitung. Engels championed the [Magyar] revolution in Hungary against both the Czechs and the Russians...

...The Magyars are not yet defeated. But if they fall, they will fall gloriously, as the last heroes of the 1848 revolution, and only for a short time. Then for a time, the Slav counter-revolution will sweep down on the Austrian monarchy with all its barbarity, and the camarilla will see what sort of allies it has. But at the first victorious uprising of the French proletariat… the Austrian Germans and Magyars will be set free and wreak a bloody revenge on the Slav barbarians.

The general war which will then break out will smash this Slav Sonderbund and wipe out all these petty hidebound nations, down to their very names. The next world war will result in the disappearance from the face of the earth not only of reactionary classes and dynasties, but also of entire reactionary peoples. And that, too, is a step forward...

A few weeks later he drove the point home:

People have learned by bitter experience that the "European fraternal union of peoples" cannot be achieved by mere phrases and pious wishes, but only by profound revolutions and bloody struggles; they have learned that the question is not that of a fraternal union of all European peoples under a single republican flag, but of an alliance of the revolutionary peoples against the counter-revolutionary peoples, an alliance which comes into being not on paper, but only on the battlefield...