I'd say it's one of a few things. 1. Survivorship bias. Things that look like long-term planning is really the result of things that remain politically expedi

I'd say it's one of a few things. 1. Survivorship bias. Things that look like long-term planning is really the result of things that remain politically expedient through the years. The Constitution is (at least) the second attempt to write laws for the nation. 2. Continuous leadership: Or how no President will ever have the influence of FDR ever again and how WWII shaped the country for years to come. When you are in charge for a while, you can plan longer. FDR won 4 terms, spent 13 years in office before dying. Navigated the country through the Depression and the second World War. Dying at the beginning of his fourth term left Truman in charge. Being his Vice President, Truman was in line with FDR's goals and continued them. And you may think Eisenhower winning the presidency next would represent a break in the leadership, but Eisenhower was the Supreme Commander of the Allied forces in WWII. He worked closely with FDR. He ran as a Republican mostly to make sure Taft didn't get the Republican nomination. He continued New Deal programs and started the Interstate Highway system. For a Republican, he was fairly progressive, continuing many social programs and starting another. Both parties wanted Eisenhower to run under their banner. He was just a generally well regarded figure. Following Eisenhower, we have Kennedy (WWII veteran), then Johnson (also WWII veteran). So for about 36 years, you had administrations that were invested in social programs. That were willing to continue the policies of previous administrations. Hell, you could probably throw Nixon (WWII veteran) on that train as well. Served as Eisenhower's VP, started the EPA. He probably represents that last vestiges of FDR's influence on the office. And George HW Bush is the last President to have served in active duty during WWII. I mean, WWII is a major pivot point for the entire world. The events that went on during that time period literally still define the world today. We hardly think about Vietnam or Korea anymore, but you can still trot out Hitler and Nazis as ultimate examples of pure evil. And even then, the Vietnamese and Korean conflicts are results of the events of WWII. So you have all those years being led by people shaped by the same world-defining event. Who saw the value in all the same things. It's not completely out of left field that their interests would line up.