Alaska Airlines, Inc. v. Brock
In Alaska Airlines, Inc. v. Brock, 480 U.S. 678, 684 (1987), the Court stated that "the more relevant inquiry in evaluating severability is whether the statute will function in a manner consistent with the intent of Congress. . . . The final test . . . is the traditional one: the unconstitutional provision must be severed unless the statute created in its absence is legislation that Congress would not have enacted." 480 U.S. at 685.
The Court pointed out that it had held in previous cases that the inclusion of such a clause creates a presumption that Congress did not intend the validity of the statute in question to depend on the validity of the constitutionally offensive provision. In such a case, unless there is strong evidence that Congress intended otherwise, the objectionable provision can be excised from the remainder of the statute. Id. at 687.