Pennhurst State School and Hospital v. Halderman, 451 U. S. 1, 17 (1981).
 South Dakota v. Dole, 483 U.S. 211 (1987).
 National Federation of Independent Business v. Sebelius, 567 US ___ (2012), 132 S.Ct 2566 (slip. op. at 51):
 Art. IV, § 4. “The United States shall guarantee to every state in this union a republican form of government, and shall protect each of them against invasion.”
 Incidentally, this is the quintessentially appropriate case to apply the “Necessary and Proper Clause.” The Left often uses it to expand Congress’ enumerated powers beyond recognition, but in this case it would support the conditioning of grants to states in order to sustain an existing enumerated power.
 Article I Section 8 of the Constitution grants Congress the plenary power over immigration. Even the Supreme Court has held that the formation of immigration policy “is entrusted exclusive to Congress,” and that “[t]he plenary authority of Congress over aliens . . . is not open to question.” Galvan v. Press, 347 U.S. 522, 531 (1954); Kleindienst v. Mandel, 408 U.S. 753, 766-67 (1972); Fiallo v. Bell, 430 U.S. 787, 792 (1977); INS v. Chadha, 462 U.S. 919, 940-41 (1983).
 Annals of Congress. The Debates and Proceedings in the Congress of the United States. "History of Congress." 42 vols. Washington, D.C.: Gales & Seaton, 1834--56. Justice Joseph Story echoed these same sentiments in 1833 in his Commentaries on the Constitution. “If aliens might be admitted indiscriminately to enjoy all the rights of citizens at the will of a single state, the Union might itself be endangered by an influx of foreigners, hostile to its institutions, ignorant of its powers, and incapable of a due estimate of its privileges,” wrote Story.