More on Bush Opening Mail

Here's more on Bush's claimed ability to open your mail. Apparently it's not clear if his signing statement is actually declaring a new power or just restating an existing one. "It may be that this signing statement is nothing, and it just reveals the Administration's willingness to issue signing statements about everything. On the other hand, it may be that it hints at a program allowing the government to open postal mail under the claimed authority of the AUMF." Isn't their claim that these signing statements are supposed to make things clearer?