“If any provision of this subtitle [subtitle C (§§ 11041–11044) of title I of div. C of Puspan. L. 107–273, enacting this chapter, amending sections 331, 332, 372, 375, and 604 of this title, and section 7253 of Title 38, Veterans’ Benefits, and enacting provisions set out as a note under section 1 of this title], an amendment made by this subtitle, or the application of such provision or amendment to any person or circumstance is held to be unconstitutional, the remainder of this subtitle, the amendments made by this subtitle, and the application of the provisions of such to any person or circumstance shall not be affected thereby.”