A constitutional moment is a period of sustained popular mobilization during which 'We the People' authorize fundamental constitutional change outside the Article V amendment process. Ackerman identifies six stages: a signaling phase where a branch responds decisively to crisis, popular mobilization, a triggering election that mandates change, mobilized elaboration through landmark statutes, a ratifying election that cements the change, and final consolidation. The New Deal, Civil War, and Civil Rights eras each qualify as such moments, producing new constitutional regimes through statutes like the 1964 Civil Rights Act rather than formal amendments.

Ackerman distinguishes between two tracks of democratic decision-making. Ordinary politics involves interest-group bargaining, legislative compromise, and judicial interpretation within an existing constitutional framework. Higher lawmaking, by contrast, occurs when the People speak directly through sustained popular mobilization, triggering elections, and landmark statutes that break sharply with the constitutional status quo. This dualist framework rejects both originalism (which binds the present to 1787) and living constitutionalism (which treats judges as primary agents of change), positioning the sovereign People as the ultimate authors of constitutional transformation.

Higher lawmaking is the process by which the People exercise their sovereign authority to create new constitutional principles that stand above ordinary legislation. Unlike Article V amendments, which require supermajorities in Congress and state legislatures, higher lawmaking proceeds through a democratic dialogue between political branches and the electorate. A branch proposes transformative legislation, the People signal their support through electoral mandates, and subsequent elections ratify the change. Ackerman argues that the New Deal's constitutionality was legitimated through this process—FDR's 1936 landslide ratified the constitutional revolution initiated by his first-term statutes, even though no formal amendment was passed.

Ackerman rejects originalism's claim that the Constitution's meaning was fixed in 1787, arguing that subsequent constitutional moments have legitimately transformed the original document's content. He also rejects living constitutionalism's reliance on judicial updating, insisting that constitutional change must flow from popular sovereignty, not judicial interpretation. His framework offers a third path: constitutional transformation through democratic mobilization that generates new principles binding on all branches, including the courts. This makes Ackerman's theory uniquely democratic among constitutional theories—it empowers the People, not judges or Framers, as the primary agents of constitutional meaning.

In *The Failure of the Founding Fathers* (2005), Ackerman shows that the Framers did not anticipate political parties or the electoral college crisis of 1800, when Republican militias threatened to march on Washington as the House deadlocked between Jefferson and Burr. Through archival research, he reveals how Jefferson counted Federalist rivals out of the House runoff and how Federalists threatened to install John Marshall as president. The Constitution survived through improvisation, not design—producing the 'plebiscitarian presidency' (a popularly mandated executive) and a Supreme Court that retreated in *Stuart v. Laird* to preserve its own survival. Ackerman argues *Stuart* was more significant than *Marbury* in establishing the early Court's relationship to presidential democracy.

In *Revolutionary Constitutions* (2019), Ackerman defends democratic populism against indiscriminate condemnation, arguing that mass popular mobilizations have produced many of the modern era's greatest constitutional achievements. He outlines four stages of revolutionary constitutionalism—mobilized insurgency, constitutionalization, succession crisis, and consolidation—and applies them to India, South Africa, post-war France, and Italy. The book also examines failures in Iran, Poland, and Myanmar, offering lessons for activists confronting authoritarian regimes. Ackerman's comparative framework provides a roadmap for understanding how popular movements can successfully establish constitutional democracy and how elites may co-opt or destroy revolutionary momentum.

In *The Stakeholder Society* (co-authored with Anne Alstott), Ackerman proposed that every young adult receive a substantial cash grant ('citizen stake') at maturity, providing a fair share of national wealth and genuine equality of opportunity. This proposal has influenced reform initiatives in Brazil, Britain, and other European nations, as well as India, serving as a model for universal basic capital grants. Ackerman's argument links economic empowerment to constitutional citizenship—without material resources, formal political equality remains hollow. The proposal continues to inform debates on wealth redistribution, child development accounts, and intergenerational justice.