Beginning after the end of Reconstruction, this chapter looks at the ways in which the police power emerged to facilitate an increasingly bold project of regulation. Key Supreme Court decisions supported the use of the police power to undertake and implement the objectives of a growing economy and a widening sphere of government. State power accompanied expanding national power and all levels of government tackled myriad persistent and new problems. In a case from the early twentieth century, for example, the Court upheld a vaccine requirement as a reasonable exercise of the public health authority of the state. Regulatory power was called into question by the Supreme Court’s Lochner-era decisions, but even this two-decades-long movement did not seriously threaten the ability of state governments to carry out ambitious regulatory agendas. Significantly, the Court put its imprimatur on the government’s zoning power in key cases from the late 1920s. And though the Court would message to the states that there were limits on how far they could go in restricting property rights, through doctrines such as “regulatory takings,” what emerged by the end of World War II was a robust conception of the state police power, one that gave government a wide sphere of action and authority to protect the general welfare.

As state and local governments moved into the infrastructure field, they also revolutionized public finance and set the stage for infrastructure politics in the twentieth century. Governments at every level broadened their fiscal footprints to accommodate new infrastructure development after the Civil War. Governments were not supposed to direct public money into private hands, but this legal principle was in inevitable conflict with the public–private model of infrastructure development. In any event, state governments created numerous workarounds, most notably by allowing cities to tax and spend instead of states doing it themselves. Finally, the Civil War fundamentally changed the balance of power between federal and state governments. The 14th Amendment seemed to promise a new era of expanded rights for black Americans and other groups against discriminatory state power. As public power spread like a web over economic life, conservative jurists such as Ernst Freund, Christopher Tiedemann, Thomas Cooley, and others asked whether there were any limits at all on government power to advance what legislatures called “the public good.” Their views would inform laissez-faire legalism from its rise after the Civil War until its demise in the 1930s.

In order to solve a constitutional problem, the constitutional lawyer will always use the basic toolkit of arguments discussed in Chapter 3, and as we saw in Chapter 4, the lawyer must also consider the ways in which institutional perspective affects how questions are shaped and answers constructed. There are, furthermore, specific clauses in the written Constitution that merit special attention.

The constitutional structure that supports our democratic system recognizes certain fundamental rights involving human liberties. These rights are considered so important that any governmental action impinging on them warrants examination under strict scrutiny, a legal standard that imposes a high bar for the government. Under strict scrutiny, the government must articulate a compelling purpose for enforcing a law encroaching fundamental rights and prove there are no less restrictive means to accomplish the law’’s purpose. Some fundamental rights, such as the freedom of speech and the right to vote, are enumerated in the Constitution. Others, including the rights to procreate, marry, exercise parental autonomy, make medical-care decisions, and others, are unenumerated yet also recognized as fundamental under the Constitution. But where do these rights come from? What, if anything, do they have in common with genome-editing technologies? This chapter examines novel issues related to genome editing and constitutional law. It surveys modern-day due process and equal protection jurisprudence to evaluate whether existing precedents define a cognizable fundamental right to select uses of germline genome editing. The chapter further illustrates the dangers of ignoring or misinterpreting science in constitutional law and analyzes the involuntary sterilization of “mentally defective”individuals legalized under Buck v. Bell.

This chapter surveys the legal history of the term "due process of law," from Magna Carta, the Statutes of Edward III, and the Petition of Right to the writings of William Blackstone and the opinions of antebellum state-level court cases. It argues that there was no concept of "substantive due process" in the antebellum period. It refutes arguments that due process prohibited class legislation, limited states to reasonable exercises of the police powers, or underwent a change in meaning as a result of abolitionist constitutional thinkers.