In June 1899, the conservative politician Pierre Waldeck-Rousseau tried to restore stability by inviting Millerand, a socialist ally of Jaurès, to join his government, which also included Gaston, Marquis de Galliffet, who had commanded the slaughter of the workers of the Paris Commune in 1871 and who had advocated the continued imprisonment of Dreyfus.
[3] The leaders of the French Workers' Party strongly opposed Millerand's move, but most of the non-Marxist left in France, led by Jaurès, supported it.
The International's leading theorist, Karl Kautsky, refused to criticize "principled ministerialism" and delegates rejected a resolution that would have banned participation in government.
Luxemburg analysed the Millerand experience in great detail and drew from it broader tactical lessons for revolutionaries that went beyond the immediate circumstances of his presence in the French government.
Her political logic, hammered out on the anvil of hard facts, closed every loophole of escape, and her final judgement has a universal validity against all attempts to serve the cause of socialism with the methods of capitalist state power.”[9]