Complex sentence: Robespierre was also convinced that the internal stability of the country was more important; this opposition from expected allies irritated the Girondists, and the war became a major point of contention between the factions.
Split into simpler sentences: Robespierre was also convinced that the internal stability of the country was more important. This opposition from expected allies irritated the Girondists, and the war became a major point of contention between the factions.