The full context of the quote makes it clearer:
In the summer of 1919, the Allied armies stood along the Rhine, and their bridgeheads bulged deeply into defeated, disarmed, and hungry Germany. The chiefs of the victor Powers debated and disputed the future in Paris. Before them lay the map of Europe to be redrawn almost as they might resolve. After fifty-two months of agony and hazards the Teutonic Coalition lay at their mercy, and not one of its four members could offer the slightest resistance to their will. Germany, the head and forefront of the offence, regarded by all as the prime cause of the catastrophe which had fallen upon the world, was at the mercy or discretion of conquerors, themselves reeling from the torment they had endured.
Churchill is calling the Central Powers (not an "official" name in any sense, in the same way that "the Allies" was not the actual name of the Entente) the "Teutonic Coalition" because of its two German-speaking members (the German and Austrian Empires), with the remaining two being Bulgaria (the "Prussia of the Balkans") and Turkey.