Sometimes simple and bold ideas help us see more clearly a complex reality that requires nuanced approaches. I have an "impossibility theorem" for the global economy that is like that. It says that democracy, national sovereignty and global economic integration are mutually incompatible: we can combine any two of the three, but never have all three simultaneously and in full.

Here is what the theorem looks like in a picture:

To see why this makes sense, note that deep economic integration requires that we eliminate all transaction costs traders and financiers face in their cross-border dealings. Nation-states are a fundamental source of such transaction costs. They generate sovereign risk, create regulatory discontinuities at the border, prevent global regulation and supervision of financial intermediaries, and render a global lender of last resort a hopeless dream. The malfunctioning of the global financial system is intimately linked with these specific transaction costs.

So what do we do?

One option is to go for global federalism, where we align the scope of (democratic) politics with the scope of global markets. Realistically, though, this is something that cannot be done at a global scale. It is pretty difficult to achieve even among a relatively like-minded and similar countries, as the experience of the EU demonstrates.

Another option is maintain the nation state, but to make it responsive only to the needs of the international economy. This would be a state that would pursue global economic integration at the expense of other domestic objectives. The nineteenth century gold standard provides a historical example of this kind of a state. The collapse of the Argentine convertibility experiment of the 1990s provides a contemporary illustration of its inherent incompatibility with democracy.

Finally, we can downgrade our ambitions with respect to how much international economic integration we can (or should) achieve. So we go for a limited version of globalization, which is what the post-war Bretton Woods regime was about (with its capital controls and limited trade liberalization). It has unfortunately become a victim of its own success. We have forgotten the compromise embedded in that system, and which was the source of its success.

So I maintain that any reform of the international economic system must face up to this trilemma. If we want more globalization, we must either give up some democracy or some national sovereignty. Pretending that we can have all three simultaneously leaves us in an unstable no-man's land.