"Thus the modern practice of genocide was born"

If you wish to understand the 20^th century, you could do much worse than starting with Paul Johnson's Modern Times (revised edition, 2001). I discovered today that the full text is available online in a variety of formats, but the physical book is worth owning. The following is from the second chapter, which deals mostly with the regimes Lenin and Mussolini created. The "Cheka" referred to below was Lenin's secret police, leading to various successors: MVD, OGPU, NKVD, KGB, Putin's Federal Security Service. Putin himself was trained by, and rose through, the KGB.

In the first six months of 1918 the Cheka executed, according to its official figures, only twenty-two prisoners. In the second half of the year it carried out 6,000 executions, and in the whole of 1919 some 10,000. W.H. Chamberlain, the first historian of the revolution, who was an eyewitness, calculated that by the end of 1920 the Cheka had carried out over 50,000 death sentences.

However, the most disturbing and, from the historical point of view, important characteristic of the Lenin terror was not the quantity of the victims but the principle on which they were selected. Within a few months of seizing power, Lenin had abandoned the notion of individual guilt and, with it, the whole Judeo-Christian ethic of personal responsibility. He was ceasing to be interested in what a man did or had done — let alone why he had done it — and was first encouraging, then commanding, his repressive apparatus to hunt down people, and destroy them, not on the basis of crimes, real or imaginary, but on the basis of generalizations, hearsay.... The watershed was Lenin's decree of January 1918 calling on the agencies of the state to 'purge the Russian land of all kinds of harmful insects'. This was not a judicial act: it was an invitation to mass murder. Many years later, Alexander Solzhenitsyn listed just a few of the groups who thus found themselves condemned to destruction as 'insects'. They included 'former Zemstvo members, people in the Coop[erative] movements, homeowners, high-school teachers, parish councils and choirs, priests, monks and nuns, Tolstoyan pacifists, officials of trade unions' — soon all to be classified as 'former people'. Quite quickly the condemned group decree-laws extended to whole classes and the notion of killing people collectively rather than individually was seized upon by the Cheka professionals with enthusiasm. Probably the most important Cheka official next to Dzerzhinsky himself was the ferocious Latvian M.Y. Latsis. He came nearest to giving the Lenin terror its true definition:

The Extraordinary Commission is neither an investigating commission nor a tribunal. It is an organ of struggle, acting on the home front of a civil war. It does not judge the enemy: it strikes him.... We are not carrying out war against individuals. We are exterminating the bourgeoisie as a class. We are not looking for evidence or witnesses to reveal deeds or words against the Soviet power. The first question we ask is — to what class does he belong, what are his origins, upbringing, education or profession? These questions define the fate of the accused. This is the essence of the Red Terror.

Once Lenin had abolished the idea of personal guilt, and had started to 'exterminate' (a word he frequently employed) whole classes, merely on account of occupation or parentage, there was no limit to which this deadly principle might be carried. Might not entire categories of people be classified as 'enemies' and condemned to imprisonment or slaughter merely on account of the colour of their skin, or their racial origins or, indeed, their nationality? There is no essential moral difference between class-warfare and race-warfare, between destroying a class and destroying a race. Thus the modern practice of genocide was born. ....

Paul Johnson, Chapter 2 "The First Despotic Utopias," Modern Times, 2001.