The Federated Republic of Europe-the United States of Europe-that is what must be. National autonomy no longer suffices. Economic evolution demands the abolition of national frontiers. If Europe is to remain split into national groups, then Imperialism will recommence its work. Only a Federated Republic of Europe can give peace to the world.

If we close our eyes to the dark sides of the workers' State which we have helped to create, we shall never reach socialism.

As long as human labor power, and, consequently, life itself, remain articles of sale and purchase, of exploitation and robbery, the principle of the “sacredness of human life” remains a shameful lie, uttered with the object of keeping the oppressed slaves in their chains.

Ideas that enter the mind under fire remain there securely and for ever.

What shall we call an "immediate possibility"? In 1923 the situation in Germany was profoundly revolutionary, but what was lacking for a victorious revolution was a correct strategy.

In a serious struggle there is no worse cruelty than to be magnanimous at an inopportune time.

All the parties of capitalist society, all its moralists and all its sycophants will perish beneath the debris of the impending catastrophe. The only party that will survive is the party of the world socialist revolution.