Being a non-attorney, I have to go by
evidence and in this case the evidence is the fact that Congress inserts the "boilerplate" severability clause in every piece of important legislation.
You're telling me that they do this for NO particular reason...since is isn't needed.
Reminds me of Obama spending millions of dollars on attorneys to block access to his birth certificate and other records...as if everyone does it.
No, they do this because it categorically shows the intent of the Congress when the language is evaluated by the the Courts later on. The test that the Court uses is legislative intent. If the Courts find that the provision is not an integral part of the legislation (that other parts of the legislation can stand alone) and that the separable was not so integral that the Congress would not have passed the law without that provision, the Court will invalidate the Unconstitutional provision, but allow the rest of the law to stand.
Legislative intent is easy to discern if the "boilerplate" severability clause is inserted. If the clause is lacking, the Court can still look to the overall intent of the Congress, it's just less clear.
Numerous provisions laws have been upheld, despite the fact that certain provisions in the law were Unconstitutional, and the law lacked a severability clause. Again, Congressional intent is the key consideration.