[hga]

Except the case preceded the war except in its winding its way through the courts, it's New Deal law, after the "switch in time that saved nine" (https://en.wikipedia.org/wiki/Switch_in_time_that_saved_nine... from later in the Wikipedia article on the case:

"In July 1940, pursuant to the Agricultural Adjustment Act (AAA) of 1938, Filburn's 1941 allotment was established at 11.1 acres (4.5 ha) and a normal yield of 20.1 bushels of wheat per acre. Filburn was given notice of the allotment in July 1940 before the Fall planting of his 1941 crop of wheat, and again in July 1941, before it was harvested. Despite these notices, Filburn planted 23 acres (9.3 ha) and harvested 239 bushels from his 11.9 acres (4.8 ha) of excess area."