When the conservatives returned to office in 1949 under Robert Menzies after eight years in opposition, McEwen became Minister for Commerce and Agriculture, switching to Minister for Trade in 1956. Menzies nicknamed him "Black Jack", due to his dark eyebrows, grim nature, and occasional temper. In the Menzies Government, McEwen pursued what became known as "McEwenism" – a policy of high tariff protection for the manufacturing industry, so that industry would not challenge the continuing high tariffs on imported raw materials, which benefitted farmers but pushed up industry's costs. This policy was a part (some argue the foundation) of what became known as the "Australian settlement" which promoted high wages, industrial development, government intervention in industry (Australian governments traditionally owned banks and insurance companies and the railways and through policies designed to assist particular industries) and decentralisation.