Lewis in his essay “Why I Am Not A Pacifist”:

[Some suggest] The removal of war must therefore be attempted. We must increase by propaganda the number of Pacifists in each nation until it becomes great enough to deter that nation from going to war. This seems to me wild work. Only liberal societies tolerate Pacifists. In the liberal society, the number of Pacifists will either be large enough to cripple the state as a belligerent, or not. If not, you have done nothing. If it is large enough, then you have handed over the state which does tolerate Pacifists to its totalitarian neighbor who does not. Pacifism of this kind is taking the straight road to a world in which there will be no Pacifists.

(Note that he’s using “liberal” in the classical sense: as opposed to totalitarian, not as opposed to conservative.)