The ultras believed their power over de Gaulle was absolute. [causal]
In "ultra" circles on the Committee of Public Safety there were already rumblings about a "second 13 May" to replace de Gaulle's Neguib by a Nasser chosen among themselves. After the Constantine speech, but before the paix des braves, Lagaillarde, Ortiz and Martel had tried to call a general strike on 16 October in protest against de Gaulle's betrayal. The idea was squashed by some plain talk from General Massu. But the seeds of later revolt had been sown; for the "ultras" would never be able to rid themselves of the notion that, as they had brought de Gaulle to power, so they could despatch him from it. Not, however, without the army.
Horne, Alistair, A Savage War of Peace- Alge…, loc. 947