¹ The phrase comes from a paper Alison Young and I wrote: N. W. Barber and A. L. Young, “The Rise of Prospective Henry VIII Clauses and their Implications for Sovereignty” [2003] Public Law 112. We may have been unconsciously inspired by Alexander Hamilton who talked of the need for ‘mutual defence’: See J. Madison, A. Hamilton, and J. Jay, The Federalist Papers, ed. I. Kramnick, No. 66, (London, 1987), 384.

² On the contrast between reasons for creation and function, see Ullmann-Margalit, E., “Invisible Hand Explanations” (1978) 39 Synthese 263CrossRefGoogle Scholar, 284–285 and P. Pettit, “Functional Explanation and Virtual Selection” in P. Pettit, Rules, Reasons, and Norms (Oxford 2002).

³ On the contrast between historical, psychological, and justificatory reasons, see N. W. Barber, The Constitutional State (Oxford 2011), 83–85.

⁴ On parliamentary privilege, see J. Chafetz, Democracy's Privileged Few (New Haven, 2007). The classic instance of this is found in the British constitution: Bill of Rights 1689, Article 9.

⁵ In the British constitution the courts have historically lacked the power to assess the reasonableness of statutes or the fairness of their creation: Pickin v British Railways Board [1974] A.C. 765. In other systems that allow for constitutional review of statutes, the grounds for review of legislation are different from, and more limited than, judicial review of administrative acts. On the United States, see Rogers, J. R., “Information and Judicial Review: A Signalling Game of Legislative Judicial Interaction” (2001) 45 American Journal of Political Science 84CrossRefGoogle Scholar and Williams, R. F., “State Constitutional Limits on Legislative Procedure: Legislative Compliance and Judicial Enforcement” (1987) 17 Publius 91Google Scholar.

⁶ This is true of the British monarch, but is also true of many presidents. On France, see C. Elliott, E. Jeanpierre, C. Vernon, French Legal System, 2^nd ed., (London 2006), 32–34. On Italy, see Quigley, B., “Silvio Berlusconi v The Italian Legal System” (2011) 34 Hastings International and Comparative Law Review 435Google Scholar.

⁷ Mastrogiacomo, T. T., “Showdown in the Rose Garden: Congressional Contempt, Executive Privilege, and the Role of the Courts” (2010) 99 Georgetown Law Review 163Google Scholar.

⁸ P. Jackson and P. Leopold, O. Hood Philips and Jackson: Constitutional Law and Administrative Law 8^th ed., (London 2001), 26; C. Turpin and A. Tomkins, British Government and the Constitution, 7^th ed., (Cambridge 2011), 147–149 shows that this convention has been placed under stress in recent years.

⁹ United States Constitution, Art. III § 1. In Ireland a constitutional amendment was required before judicial pay could be reduced: P. O'Brien “Judicial Independence and the Irish Referendum on Judicial Pay” available on the United Kingdom Constitutional Law Blog (http://ukconstitutionallaw.org).

¹⁰ India provides the most extreme example of this of which I am aware: Levinson, S., “Identifying Independence” (2006) 86 Boston Law Review 1297Google Scholar.

¹¹ As in Britain: Bill of Rights 1689, Art. 4, Turpin and Tomkins, note 8 above, 644–649. See also R. Weill, “We The British People” [2004] Public Law 380. The tightness of the connection in the modern constitution between the legislative and executive branch entails this power is rarely used against the executive. In America, in contrast, this power is regularly exercised: Chafetz, J., “Congress's Constitution” (2012) 160 University of Pennsylvanian Law Review 715, 725–731Google Scholar.

¹² See Cass Sunstein's careful discussion of the power in an American context, arguing that impeachment should be used when the president abuses the powers he has by virtue of being president – and so not simply for ordinary wrong-doing: C. Sunstein, Designing Democracy: What Constitutions Do (Oxford, 2001), chapter 5; Chafetz, J., “Impeachment and Assassination” (2010) 95 Minnesota Law Review 347Google Scholar. There is also a residual power of impeachment in the British constitution: see Jackson and Leopold, note 8 above, 154–155.

¹³ As in the United Kingdom: Barber and Young, note 1 above.

¹⁴ In the European Union national parliaments are given a limited power to compel the Commission to rethink a legislative proposal that national parliaments believe runs contrary to the principle of subsidiarity: Article 5(3)–(4) TEU, Protocol (No.2) “On the Application of the Principles of Subsidiarity and Proportionality” discussed in Cooper, I., “A Virtual Third Chamber For the European Union? National Parliaments After the Treaty of Lisbon” (2012) 35 West European Politics 441CrossRefGoogle Scholar.

¹⁵ There is an ornamental power of veto in the British constitution: Turpin and Tomkins, note 8 above, 385–386. A more potent veto power is found in the American constitution: McCarty, N. M., “Presidential Pork: Executive Veto Power and Distributive Politics” (2000) 94 American Political Science Review 117CrossRefGoogle Scholar. According to Hamilton, the primary reason for the veto was to allow the executive to defend itself: The Federalist Papers, note 1 above, No. 73, 419–420.

¹⁶ H. Klug, The Constitution of South Africa: A Contextual Analysis (Oxford 2010), 199.

¹⁷ This is the case in many parliamentary systems – see, for example, C. Saunders, The Constitution of Australia: A Contextual Analysis, (Oxford 2011), 120–121; see also Youngs, R. and Thomas-Symonds, N., “The Problem of the ‘Lame-Duck’ Government: A Critique of the Fixed-Term Parliament Act” (2012) 65 Parliamentary Affairs 1Google Scholar.

¹⁸ As in America: B. Ackerman, We The People: Transformations, vol. 2, (Cambridge Mass., 1998) chapter 1. See also, Weill, R., “Evolution vs. Revolution: Duelling Models of Dualism” (2006) 54 American Journal of Comparative Law 429, 453–456CrossRefGoogle Scholar.

¹⁹ Vladeck, S. I., “Boumediene's Quiet Theory: Access to Courts and the Separation of Powers” (2008) 84 Notre Dame Law Review 2107Google Scholar; Berger, R., “Bills of Attainder: A Study of Amendment by the Court” (1978) 63 Cornell Law Review 355Google Scholar; J. Jowell, “The Rule of Law and its Underlying Values”, in J. Jowell and D. Oliver eds., The Changing Constitution, 7^th edn., (Oxford 2011), 5–24.

²⁰ An extreme, and atypical, example of this is found in the Chinese system, in which the practice of ‘benign violation’ has almost reached the level of a recognized constitutional principle: Q. Zhang, The Constitution of China, (Oxford 2012), 59–62. See also Barber, note 3 above, 90–95.

²¹ See Oliver, D., “Constitutional Scrutiny of Executive Bills” (2004) 4 Macquarie Law Journal 33Google Scholar, discussing the Asylum and Immigration Bill 2004, which was altered after the Lord Chief Justice, Lord Woolf, publically warned that judges might decline to give effect to its provisions.

²² Fallon, R., “Executive Power and The Political Constitution” (2007) 1 Utah Law Review 1Google Scholar, 8–9.

²³ This is a significant practical limit on the Court of Justice of the European Union and the European Court of Human Rights, both of which depend on the support of their signatory states: J. Weiler, “Federalism Without Constitutionalism: Europe's Sonderweg” in K. Nicolaidis and R. Howse, eds., The Federal Vision, (Oxford 2001). See also N. E. Devins and L. Fisher, The Democratic Constitution, (Oxford, 2004), chapter 1.

²⁴ See the discussion in Barber, note 3 above, 90–95.

²⁵ Mahud, T., “The Jurisprudence of Successful Treason” (1994) 27 Cornell International Law Journal 49Google Scholar; Barber, N. W., “The Doctrine of State Necessity in Pakistan” (2000) 116 Law Quarterly Review 569Google Scholar.

²⁶ Barber, note 3 above, 112–114.

²⁷ See the discussion in Chafetz, note 11 above, 731–734.

²⁸ W. B. Gwyn, The Meaning of the Separation of Powers: an analysis of the doctrine from its origin to the adoption of the United States Constitution (Tulane 1965), chapter one; Banks, W. C., “Efficiency in Government: Separation of Powers Reconsidered” (1984) 35 Syracuse Law Review 715Google Scholar; Sharp, M. P., “The Classic American Doctrine of the Separation of Powers” (1935) 2 The University of Chicago Law Review 385CrossRefGoogle Scholar.

²⁹ Myers v US (1926) 272 U.S. 52, 293; see also C. Montesquieu, The Spirit of the Laws (Cambridge 1989) Book 19, chapter 27; E. Barendt, “Separation of Powers and Constitutional Government” [1995] Public Law 599, 605–606; Calabresi, S. and Rhodes, K., “The Structural Constitution: Unitary Executive, Plural Judiciary” (1992) 105 Harvard Law Review 1153CrossRefGoogle Scholar, 1156, where separation of powers is described as ‘institutionalising conflict’.

³⁰ M. Vile, Constitutionalism and the Separation of Powers, 2nd ed., (Indianapolis 1998), 14.

³¹ I. Berlin, “Two Concepts of Liberty” in I. Berlin, Four Essays on Liberty (Oxford 1969).

³² See, for example, J. Raz, The Morality of Freedom (Oxford 1988), chapter 15, and J. Waldron, “Constitutionalism – A Sceptical View” in T. Christiano and J. Christman, Contemporary Debates in Political Philosophy (Oxford 2009).

³³ N. Komesar, Imperfect Alternatives (Chicago 1996); Rubin, E., “The New Legal Process” (1996) 109 Harvard Law Review 1393CrossRefGoogle Scholar. King, J., “Institutional Approaches to Judicial Restraint” (2008) 28 Oxford Journal of Legal Studies 409, 423–425CrossRefGoogle Scholar.

³⁴ Barber, N. W., “Prelude to the Separation of Powers” (2001) 60 Cambridge Law Journal 59CrossRefGoogle Scholar; E. Carolan, The New Separation of Powers (Oxford 2010).

³⁵ Gwyn, note 28 above, 32–34; A. S. Anderson, “A 1787 Perspective on the Separation of Powers”, in R. Goldwin and A. Kaufman eds., The Separation of Powers – Does it Still Work? (Washington 1987), 145; D. Morgan, The Separation of Powers in the Irish Constitution (Dublin 1997), 4; P. Laslett, in J. Locke, Two Treatises of Government (ed. P. Laslett, Cambridge 1988),118–120; Peabody, B. and Nugent, J., “Toward a Unifying Theory of the Separation of Powers” (2003–2004) 53 American University Law Review 1, 26Google Scholar.

³⁶ Madison, note 1 above, especially No. 47.

³⁷ Ibid, No. 37, 243. Madison wrote: ‘Energy in government is essential to that security against external and internal danger and to that prompt and salutary execution of the laws which enter into the very definition of good government.’ Montesquieu might have agreed: Sharp, note 28 above, 391.

³⁸ M. Farrand, The Records of the Federal Convention of 1787, vol. III, 108 (New Haven, 1966).

³⁹ See Carolan, note 34 above, chapter 25–37; Ackerman, B., “The New Separation of Powers” (2000) 113 Harvard Law Review 634, 639CrossRefGoogle Scholar.

⁴⁰ I discuss the purpose of the state and its connection to citizenship in greater detail in N. W. Barber, The Constitutional State (Oxford 2010), chapters 2 and 3.

⁴¹ Ibid., chapter 3.

⁴² See Eylon, Y. and Harel, A., “The Right to Judicial Review” (2006) 92 Virginia Law Review 991Google Scholar for an argument for judicial review that rests on the different ways that citizens can engage with legislation through different institutional structures.

⁴³ On pure theory see: Vile, note 30 above, chapter 1; Gwyn, note 28 above, chapter 1.

⁴⁴ Philips, O. Hood, “A Constitutional Myth: Separation of Powers” (1977) 93 Law Quarterly Review 11Google Scholar.

⁴⁵ On comity and the separation of powers, see T. Endicott, Administrative Law, 2^nd. ed., (Oxford 2011), 14–25.

⁴⁶ P. Yowell, Practical Reason and the Separation of Powers (D.Phil submitted to Oxford University, 2010), chapters 4 and 5.

⁴⁷ T. Endicott, Vagueness in Law (Oxford 2000), chapter 9.

⁴⁸ Fuller, L., “The Forms and Limits of Adjudication” (1978) 92 Harvard Law Review 353CrossRefGoogle Scholar.

⁴⁹ I discuss invisible hand systems in far greater detail in N. W. Barber, “Invisible Hand Systems and Authority”, paper on file with author.

⁵⁰ A. Vermeule, The System of the Constitution (Oxford 2012), chapter 3.

⁵¹ For an argument that James Madison was influenced by invisible-hand arguments, see Prindle, D. “The Invisible Hand of James Madison” (2004) 15 Constitutional Political Economy 233CrossRefGoogle Scholar – though note that Prindle has a different understanding of an invisible hand mechanism to that used in this paper. See also Chafetz, note 11 above, 772–774.

⁵² R. Dworkin, “Hard Cases” in R. Dworkin, Taking Rights Seriously (London 1977), 82–100; Yowell, P., “A Critical Examination of Dworkin's Theory of Rights” (2007) 52 American Journal of Jurisprudence 93, 108–111CrossRefGoogle Scholar; King, J., “Institutional Approaches to Judicial Restraint” (2008) 28 Oxford Journal of Legal Studies 409, 416–420CrossRefGoogle Scholar.

⁵³ And in places he seems to give up the distinction entirely: see R. Dworkin, Law's Empire (London, 1986), 208–215, where statutes are presented as potentially embodiments of principle.

⁵⁴ Carolan, note 34 above.

⁵⁵ Ibid., 129, 185.

⁵⁶ Ibid., 129.

⁵⁷ Ibid., 151–152, 177.

⁵⁸ Ibid., 128.