This article is about how FDR changed the presidency (which I think we can probably all agree on, whether or not we agree on how it changed). I think, though, that a nod also needs to be made to TR here!
The New Deal never fully solved the depression but it did stabilize the financial system and bring the economy back from the brink. Only concerted action by Washington could have produced such accomplishments as FDIC, the separation of commercial and investment banking, creation of the SEC, farm subsidies to bolster agricultural prices, public works programs such as the TVA, Civilian Conservation Corps, PWA, WPA, and a host of others that left a positive and lasting imprint on American life. Those who grumble that the New Deal destroyed capitalism could not be more wrong; it saved the capitalist system to live another day, which was Roosevelt’s intention all along.
The New Deal brought with it a federal government that intervened more actively and directly in the economy and other areas of American life. It gave Americans such social welfare programs as Social Security and unemployment insurance, the last major industrial nation to do so. Washington became a major player in the lives of many more Americans than ever before. However, it was World War II that grew the federal government far beyond even the New Deal years. This first truly global conflict, fought on three continents on a scale never before witnessed, forced the federal government to expand its existing roles and take on new ones to harness the resources needed to wage war on such far-flung fronts.
Between 1933 and 1945 Roosevelt issued an average of 307 presidential directives a year; previous presidents averaged only 85, beginning with the first one by Abraham Lincoln in 1862. Among other things these directives created 200 new federal boards, bureaus, agencies, and commissions. As late as 1939 the Congressional Directory needed only a single page to list the entire White House staff; by 1944 it required thirteen pages of small type for the 687 people directly employed by the president. The Federal Register began life in March 1936. By June 29, 1944, it had printed 76,541 directives, orders, grants, permissions, and prohibitions consuming 62,202 printed pages and 93 million words. These numbers only hint at the growth of the federal government brought about by the gargantuan task foisted on it by the war.