What started the Suez affair, and who was the first belligerent?
Short answerThere is no single simple starting point: the answer places the fighting within a long dispute over foreign control and separates Nasser's later political victory from the immediate military result.
NotesThe crisis has no single uncontested starting gun. Egyptian resentment of foreign control had a much longer history, while canal nationalisation did not itself reverse every military fact on the ground. Israel was not driven back, Egypt lost practical control during the fighting, and the canal became an immediate economic burden. Nasser nevertheless converted that battlefield and economic setback into a durable political victory, which helps explain why later public memory differed sharply from the operational result.