Paleomagnetism and the pendulum of power

Geologists use the discipline of paleomagnetism to measure the Earth’s magnetic field as it existed millions of years ago. When molten rock cools, magnetic minerals align with the planet’s magnetic field – locking in a record of the direction it pointed at that moment in time. By studying those ancient alignments, scientists can see how the Earth’s magnetic field has reversed again and again throughout history.

American federalism has its own version of this phenomenon.

As public priorities shift, our political orientation – particularly the role we assign to the federal government – tends to realign accordingly. What begins as a broad assertion of national interest can settle into law or agency structure, preserving the ideological climate of the moment like cooled lava. Then, over time, the cultural compass turns again. Federal initiatives are challenged, reshaped, or dissolved – and local control reasserts itself, at least until the pendulum swings back.

We’ve seen this happen in education, health care, criminal justice, environmental policy, and more. These are not always constitutional shifts; more often, they reflect political realignment driven by elections, economic fears, or cultural tensions. The federal government expands during crises – wars, depressions, pandemics – and then retreats when the public mood grows wary of overreach.

A prime example is the shifting stance on criminal justice and capital punishment. In the 1990s, both major parties supported tough-on-crime legislation at the federal level. Today, criminal justice reform is increasingly state-led, with some states abolishing the death penalty and others doubling down. Support for federal sentencing reform now crosses ideological lines, with states reclaiming autonomy on questions once seen as nationally uniform.

The tendency to expand and contract national authority – is not necessarily a flaw. It’s a feature of a flexible federal system. Yet it does open the door to what might be called selective federalism: the tendency to favor local control when it aligns with one’s goals and to demand national action when it doesn’t.

It’s not hypocrisy so much as convenience. One year, local control is the rallying cry; the next, federal uniformity is the moral imperative. The problem arises when we forget to ask a more fundamental question: What is the legitimate role of government at any level?

In an age when public opinion shifts quickly – and often shallowly – we would do well to revisit the true compass that guides us: the Constitution. It does not give us all the answers, but it offers durable principles. It reminds us that federal powers are limited and enumerated and that the states retain broad authority, constrained only by the individual rights all Americans share.

Paleomagnetism doesn’t judge which direction is right – it simply records what was. But we have the luxury, and the responsibility, of judgment. If we want coherence in our governance, we must do more than react to momentary winds. We must commit to a principled understanding of what government is for – and what it is not.

As the pendulum of power swings again, let us be less concerned with who holds it, and more thoughtful about why government exists.