One broad category of exception to the requirement of a warrant is “exigent circumstances.” Generally speaking, if there are exigent circumstances (e.g., a danger that evidence is about to be destroyed), a warrant is not required. Thus, to construe the act as permitting warrantless searches in cases of exigent circumstances such as the possible presence of hazardous materials, means that in this regard, the act did not make any change in pre-existing law.
So what President Bush is saying is that he understands that law enforcement authorities have exactly the same power to open first class mail that the had prior to the enactment of the Postal Accountability and Enhancement Act, at least with respect to exigent circumstances and FISA-authorized searches.
The interesting question is whether Congress really did intend to limit the power of law enforcement agencies to open mail under these circumstances. This comment by Henry Waxman, quoted by the Daily News, suggests that it may have: [...]
Is Waxman really saying that the intent of Congress is that mail can never be opened without a warrant, even, for example, if there is good reason to think it contains anthrax? If so, there is an interesting story here. But it is exactly the opposite of the “scoop” claimed by the Daily News: If President Bush is wrong, and the 2006 statute did effect a change in pre-existing law, then Congress cut back on the ability of law enforcement agencies to protect the public in circumstances of extreme danger.
The media’s narrative about White House spying and its anti-administration bias on the issue of signing statements demonstrate a pervasive blindness to the problem of congressional abuses of power. Whenever Congress and the president differ on constitutional questions (especially when the president expresses those differences in a signing statement), the media consistently operate under the assumption that the president is trying to usurp power that rightfully belongs to Congress. It’s an assumption that often leads them to get stories like this one completely backwards.