Ever since the United States Federal government assumed state debts back in 1790, the creation of a permanent national debt has been a key feature of federalization. The current national debt crisis may lead to a reversal of federalization or to the elimination of the last vestiges of the rights of states.
The situation in the European Union is much the same, where the collapse of weaker state economies may bring it down altogether, or may usher in the end of nationhood in Europe.