The Center for Freedom and Prosperity Foundation has released a study, Territorial Taxation for Overseas Americans: Section 911 Should Be Unlimited, Not Curtailed. Here is the abstract:

The U.S. is among the tiny handful of nations that imposes double-taxation on the labor income that individuals earn in other nations – even if the U.S. citizen is a full-time resident of the foreign jurisdiction. Yet since the "foreign-source" income of U.S. citizens already is subject to all applicable taxes that exist in other jurisdictions, an additional layer of U.S. tax is double-taxation – thus violating one of the most important principles of good tax policy. Almost every other country in the world taxes only income earned inside national borders – the common-sense principle of "territorial taxation." American legislators have tried to mitigate the adverse impact of worldwide taxation by allowing workers to protect annual earnings up to $80,000 from double-taxation. This policy, known as the § 911 exclusion, is a small step in the right direction. Ideally, the U.S. government should not be taxing any income earned abroad – just as foreign governments should not be taxing any income earned in America. If policy makers created a level playing field by making § 911 universal, more Americans could find jobs in the global economy, U.S. companies would become more internationally competitive, and U.S. exports would substantially increase.

See the press release here.