De Gaulle's Algerian policy drove loyal generals to resign. [causal]
Back in 1958, at the time of confusion preceding de Gaulle's takeover, Challe had seemed the embodiment of the ideal republican general, leaning if anything towards the Socialists. To his friend Guy Mollet he had remarked, "If this business goes on any longer, only de Gaulle will be capable of putting things back into order," concluding emphatically: "For my part, I will never fire on my comrades in arms." The series of disillusions that he had suffered as de Gaulle's Commander-in-Chief in Algeria have already been amply traced; then had come the President's "Algérie algérienne" speech of 4 November 1960, while Challe was commanding N.A.T.O.'s Central Europe theatre at Fontainebleau. Switching off the television, he confided to his diary: "From this moment I shall begin to think deeply about the sense of my remaining in the army." Feeling increasingly a sense of futility at Fontainebleau, on 30 December Challe had offered his resignation. In giving his reasons to Debré, Challe had condemned the prospect of any Algerian government being formed by the G.P.R.A. — which was where he felt de Gaulle's policy was leading. This would inevitably result in a "blood bath" and his conscience would not permit him to remain in the army.
Horne, Alistair, A Savage War of Peace- Alge…, loc. 1344