Ridden by Jean-Claude Desaint, he started the 9/4 second favourite and finished second, beaten a neck by Un Reitre, with the future Grand Critérium winner Dragon two lengths away in third place.
In the Prix du Jockey-Club at Chantilly Racecourse on 8 June, Argument produced his worst effort of the season as he finished last of the fourteen runners behind the 54/1 outsider Policeman.
He then traveled to Germany for the Grosser Preis von Baden in which he finished fifth behind Nebos: Desaint was fined by the local racecourse stewards for his riding performance in a rough and slowly run race.
[4] After his run in the Arc, Argument was bought privately (for a sum reported to be "in excess of $1 million"[5]), by the partnership of Bruce McNall and Berry Gordy and was transferred to the stable of Maurice Zilber.
His new owners accepted an invitation for the colt to represent France in the Washington, D.C. International at Laurel Park Racecourse on 8 November when he was ridden for the first time by Lester Piggott.
Argument started favourite for the Group One Prix Ganay at the same course on 3 May, and produced an impressive performance, sprinting clear of the field and winning by three lengths from Armistice Day and In Fijar.
[8] On 30 August, Argument was sent to Chicago to represent France in the inaugural running of the Arlington Million, then the world's most valuable horse race,[9] and finished sixth behind John Henry.
[8] For his final two races, Argument competed in North America, finishing fourth behind Open Call in the Canadian International Stakes and seventh to Providential in the Hollywood Turf Cup.
In the official International Classification he was rated the best horse trained in France and equal-second among all European racehorses, level with Ela-Mana-Mou and one pound below Moorestyle.