In response to a friend's inquiry, I've been doing a little more digging into the relationship between modernization theory and concepts of European integration. There appear to have been homologies and sympathies, if not a common point of origin, between these efforts in the 1940s. Specifically, I've been looking at the connections between Walt Rostow, the Marx of the modernization movement, and Jean Monnet, commonly seen as the intellectual architect of the European Union.
As Assistant Chief of the German-Austrian Economic Division at the State Department in 1945, Walt Rostow argued in favor of a Council of Europe within the United Nations that would include all European countries, including the Soviet Union. It was in this context that he first met Monnet in the spring of 1946, when Monnet was in Washington negotiating postwar loans for France. Rostow contacted Monnet through his older brother Eugene, who had known Monnet since 1943, when both were in North Africa. Walt had Eugene lobby Monnet personally to support Rostow's idea for a unified Europe, and Monnet accepted this idea. This proposal was approved by the UN General Assembly in December 1946. So: the personal connection there.
At a more ideological level, what connects Rostow and Monnet is the shared vision of refashioning the world along American lines. Apparently modernization was the linchpin of European unity in Monnet's mind. In a quote I haven't been able to corroborate, but which appeared in the Economist in 1994, Monnet is said to have told Rostow in 1947 that, "First we must modernise France. Without a vital France there can be no Europe. Then we must unite Western Europe. When Western Europe unites and gathers its strength, it will draw in Eastern Europe. And this great East-West Europe will be of consequence and a force for peace in the world."
As this quote suggests, both modernization theory and European integration were based on essentially universalist, cosmopolitan visions of global homogenization under a liberal banner. In calling these projects "universalist," however, we should emphasize that these were not Hegelian programs of ecumenical reconciliation of all the elements in a unified whole that would sublate the essences of each state in a higher order. Rather, they were universal projects that sought to remake and homogenize societies wholesale. The goal, in short, was to liberate by making everyone a liberal.