William Morris in 1887 when there were rumours of a war with Germany:
“If war really becomes imminent our duties as Socialists are clear enough, and do not differ from those we have to act on ordinarily. To further the spread of international feeling between the workers by all means possible, to point out to our own workers that foreign competition and rivalry, or commercial war, culminating at last in open war, are necessities of the plundering classes, and that the race and commercial quarrels of these classes only concern us so far as we can use them as opportunities for fostering discontent and revolution; that the interests of the workers are the same in all countries and they can never be really enemies of each other; that the men of our own labouring classes therefore, should turn a deaf car to the recruiting sergeant, and refuse to allow themselves to be dressed up in red and be taught to form a part of the modern killing machine for the honour and glory of a country in which they have only the dog's share of many kids and few halfpence—all this we have to preach always. though in the event of imminent war we may have to preach it more emphatically”.
Rosa Luxemburg during the first World War:
"All demands for complete or gradual disarmament, for the abolition of secret diplomacy, for the dissolution of the great powers into smaller nationalities and all similar propositions, are absolutely Utopian so long as capitalist class rule remains in power. For capitalism, in its present imperialistic course, to dispense with present-day militarism, with secret diplomacy with the centralization of many national slates, is so impossible that these postulates might more consistently, be united into the simple demand ‘abolition of capitalist class society'".