Rather than considering legal and judicial arenas as the mere surface of the weighty social processes that shape European integration, this article contends that they are actually one of the essential spaces where the government of Europe is being produced. To account for this paramount role played by law in EU polity, two hitherto unexplored research paths are followed. First of all, a socio-historical perspective focuses on the critical junctures at which Law has been formalized as a science of European government providing critical devices for integration. Second, a more sociological stance is taken in relation to the functioning of the “European legal field” (ELF). A preliminary inquiry leads to its characterization as weak, with porous internal and external borders. This article argues that this weak autonomy is what makes it strong and influential when it comes to shaping the representations and principles of EU government.