Who spoke against laissez-faire during World War 2?

During World War II, economist John Maynard Keynes was a prominent critic of laissez-faire economics. He argued that government intervention was necessary to manage economic instability and promote recovery during the war. Keynes believed that active fiscal policies could help mobilize resources and stimulate demand, contrasting sharply with the laissez-faire approach that advocated minimal government involvement in the economy. His ideas significantly influenced post-war economic policy and the role of government in economic management.