It’ll be upheld, especially with past appointments.

American federalism today is a highly institutionalized mix of dualism, cooperation, and coercion that makes it hard for presidents to alter. Long-term trends point to more centralization and polarization, even while states and localities remain independently innovative on many fronts. President Donald Trump, who has never publicly tweeted or spoken the word “federalism,” will not reverse those trends.

Trump’s biggest impact to date on federalism was the Tax Cuts and Jobs Act (2017), which capped at $10,000 the amount of state and local taxes taxpayers can deduct from their federal income-tax liability. The uncapped deduction dated back to 1862. The cap adversely affects taxpayers in high-tax Democratic states such as California more than those in lower-tax Republican states.

Trump’s biggest impacts on federalism in the long-term will flow from his Supreme Court appointments. More conservative justices will be more friendly to state powers, though not across the board or always for federalism reasons. For instance, because authority for culture-war issues such as abortion and LGBTQ rights historically resided in the states, conservative justices will resuscitate some of that authority; elsewhere, as in commerce and gun regulation, they will often assert federal authority over the states.

Otherwise, consistent with American federalism’s dualism (where power is divided between the federal government and the states rather than being shared), states still exercise policy autonomy in many ways: for example, legalizing medical and recreational marijuana and physician-assisted suicide, and pursuing climate-change initiatives, charter schools, abortion rules, consumer protection, occupational licensing, and autonomous-vehicle regulation.

How dual federalism can curtail a transgressive president

Dual federalism has four foundations. First is the US Constitution, whereby limited powers are delegated to the federal government; all other powers remain with the states. The Constitution is thus silent about such matters as consumer protection, education, environmental protection, health care, corporation charters, and local government.

Dualism further allows state officials, such as governors and attorneys general, to sue the federal government to block policy initiatives. Democratic attorneys general have filed an unprecedented number of lawsuits against Trump’s policies—many successful. Additionally, New York State shut down Trump’s charitable foundation in 2018; several attorneys general are investigating his businesses; and pardons Trump might give his compatriots for federal crimes will not shield them from state prosecutions.

Second, in Sturges v. Crowninshield (1819), the Supreme Court said states can exercise powers delegated exclusively to Congress so long as Congress does not preempt them or the court does not find them in violation of interstate commerce. States can thus legislate in areas of exclusive federal power when the federal government is unable or unwilling to act.

Third, in Prigg v. Pennsylvania (1842), the court said states were not obligated to enforce the 1793 Fugitive Slave Act. States could pass “personal liberty” laws prohibiting state and local officials from apprehending runaway slaves. Prigg established the foundation for the court’s anti-commandeering doctrine articulated in Printz v. United States (1997), for state legalizations of marijuana despite its federal illegality, and for sanctuary jurisdictions whose officials refuse to cooperate with federal immigration authorities.

Fourth, in Michigan v. Long (1983), the court held that state high-court rulings that increase rights protections above standards set by the US Supreme Court under the US Bill of Rights cannot be reviewed by the Supreme Court when based solely on “adequate and independent” state constitutional grounds.

These facets of dual federalism can blunt transgressive presidential behavior.