“War is a dispute about the measurement of power,” the historian Geoffrey Blainey wrote half a century ago. Earlier this year, Russian President Vladimir Putin took the measure of Russia’s power, and of Ukraine’s, and figured that the disparity promised a quick victory. Much of the rest of the world shared his assessment. The months since have revealed just how faulty these measurements were.

The essays in this issue’s lead package explore what power is and how it functions in the world today. Lawrence Freedman considers Russia’s battlefield setbacks and attributes them to failures that frequently afflict military power—an overestimation of “the raw force of arms,” a neglect of “command,” and “the familiar but catastrophic mistake of underestimating the enemy.” Ngaire Woods sees Putin’s delusions as just an extreme example of the “blind spots” of a broader range of leaders “enamored of their own might.”

In a time of sharpening geopolitical tensions, Daniel Drezner highlights a worrying dynamic in how the key antagonists view the trajectory of their power: all are pessimistic, which induces “risky actions in the present to forestall further decline, which can lead to arms races and brinkmanship during crises.” Maria Repnikova describes the distinct visions of “soft power” that the United States and China have brought to their competition and the threats that both visions face.

The final three essays attempt to identify the underlying drivers of international power. Michael Mazarr surveys the rise and fall of powers across history and identifies the seven sources of national dynamism that explain far more than foreign policy strategies. Barry Eichengreen assesses the state of U.S. economic influence, which remains strong but faces risks in the years ahead. And Amitav Acharya focuses on what he calls “power within”—the underappreciated strength and influence that a country gains abroad from tackling exclusion and hierarchy at home.

As these authors grapple with the nature and balance of power today, the stakes are more than academic. For as Blainey pointed out, if war results from errors in calculation, peace “marks a rough agreement about measurement.”

—Daniel Kurtz-Phelan, Editor