>>I think there should be a law that if a US citizen abandons their citizenship (especially a rich one like this b$tch) they should never be allowed to enter the US again.

The issue is that US citizens have to pay tax on their worldwide income. If she also has European citizenship and is living in Europe there will be all sorts of cross-border taxation issues, imputation and a whole load of complexity- believe me. This may simply be a pragmatic business decision along the standard "it's all about me" lines to be expected of the wealthy in 2012: allegiances and statuses are to be assessed purely according to their financial impact on me. The idea that citizenship may have a greater moral or societal value is only for the middle class scrabblers.