National Interest

by James Holmes

    The 2026 National Defense Strategy sets striking new priorities for the Pentagon—but can hardly be described as “isolationist” in character.

    The latest in a family of documents detailing the Donald Trump administration’s foreign-policy vision dropped late last month. And it is a doozy. The 2026 National Defense Strategy echoes the macro themes from its parent directive, the 2025 National Security Strategy. Where the National Security Strategy spells out basic principles guiding foreign policy and strategy, the National Defense Strategy explains in more concrete terms how the U.S. military apparatus intends to help put the administration’s vision into practice.

    Doubtless some readers will find the strategy’s blunt tone jarring. It reflects the style favored by Secretary of Defense Pete Hegseth and by the commander-in-chief himself. It even gave me, a practitioner of softly, softly diplomacy, pause. But the substance is solid, if arguable, the document is refreshingly short and the writing gallops along. Read the whole thing. It repays the effort.

• The 2026 NDS Is Not an Isolationist Document

    Four things about the National Defense Strategy are worth spotlighting in particular. First, the strategy follows the National Security Strategy’s lead in elevating the Western Hemisphere to top priority among U.S. strategic priorities. It downgrades the Indo-Pacific to a close second place, Europe to a not-so-close third place and other regions to also-ran status. The Monroe Doctrine, the Theodore Roosevelt Corollary and the “Trump Corollary” to the Doctrine put in appearances.

    In his cover memo, Secretary Hegseth disclaims the notion that reshuffling regional priorities means the administration and the republic have turned isolationist. And he’s right to do so. A directive that proclaims that the United States will reassert supremacy across half the globe, deter its prime extraregional antagonist, China and help allies help themselves to manage tough neighborhoods, is not an isolationist directive by any meaningful standard.

    Washington espies a brave new world. But it’s not one marked by American isolationism. Retrenchment, maybe.

    Was the United States ever isolationist  Well, no. In the late 1990s, University of Pennsylvania historian Walter McDougall published my favorite diplomatic history of the United States, a sprightly work titled Promised Land, Crusader State. Long story short, Professor McDougall dates the break between the early, promised land and later, crusader state phases of U.S. diplomatic history to 1898, when the United States evicted the Spanish Empire from its island holdings in the Caribbean Sea and Western Hemisphere and wrested them away for itself. It burst out of North America for the first time in a major way. Few could say it was isolationist after the splendid little war with Spain. Increasingly it asserted itself.

    Yet McDougall contests the commonplace notion that the United States was an isolationist republic even before 1898. True, giants of the American Founding such as George Washington and Thomas Jefferson did warn against the perils of entangling alliances. Still, McDougall insists—and I concur—that it’s a mistake to label pre-1898 US foreign policy isolationist. Genuinely isolationist powers seclude themselves from the outside world almost entirely; think imperial Japan for the quarter-millennium preceding the Meiji Restoration of 1868. Now that was isolationism.

    By contrast, the United States sought commerce across the globe from its inception. It never secluded itself as the Japanese did. In fact, the sail merchantman Empress of China left New York Harbor for the Celestial Empire on a trading expedition on the same day in 1784 that the ship bearing articles of peace concluding the American War of Independence set sail for Great Britain. In short, America lost no time seeking commercial and diplomatic access to important rimlands. Nor did it neglect to furnish naval protection for the mercantile fleet. The US Navy stationed a squadron in the Mediterranean Sea starting during the Jefferson presidency to guard against Barbary State predations and it established an Asiatic squadron during the Andrew Jackson administration during the 1830s.

    So much for a recalcitrant republic. Washington and Jefferson counseled non-entanglement and these were master wordsmiths. They phrased their advice precisely. Far from isolating itself from the wider world, they beseeched the United States to bide its time. The new republic should avoid embroiling itself in foreign wars until it had amassed sufficient national power to—in the words of Washington’s “Great Rule” for U.S. diplomacy, expressed in his 1796 Farewell Address—“choose peace or war, as our interest, guided by justice, shall counsel.”

    Averting war meant abjuring standing military alliances. Yet the Founding Fathers’ foreign-policy strictures had a shelf-life. In light of this, Walter McDougall pronounces unilateralism a better descriptor than isolationism for nineteenth-century U.S. foreign policy. Unilateralist U.S. leaders refused to oblige the republic to act in advance of this or that contingency. They picked and chose foreign commitments depending on ambient circumstances. That meant refraining from extraregional military adventures before 1898.

    I daresay Hegseth and Trump would agree to rebrand isolationism as unilateralism.

• The NDS Needed to Set Priorities

    Second, the National Defense Strategy proclaims anew a fundamental verity: no strategic competitor, no matter how musclebound, can afford to do it all, everywhere, at all times. It might suffice in undemanding times, but not in demanding times. The strategy terms this the “simultaneity problem,” and it is inescapable in strategic affairs. If nothing else, strategy is a process of setting and enforcing priorities. The contender that tries to accomplish everything, everywhere, all the time, generally ends up accomplishing little, anywhere. Trying to do it all thins out finite resources at any one scene of competition or conflict, risking defeat everywhere. That being the case, the wise competitor focuses preponderant resources at scenes of action that matter most—and bolsters its chances of success in these select contingencies.

    A unilateralist strategy like the National Defense Strategy frankly declares that some theaters exert a more pressing claim than others on US diplomatic, economic and military resources. It allocates resources accordingly.

    Prussian martial sage Carl von Clausewitz explains how to measure commitments against one another and apportion resources—or not—to each. Clausewitz obsessed over prevailing in the primary theater designated by political and military magnates. It mattered most in their estimation. He did, grudgingly, allow that the leadership might pursue a lesser theater or endeavor on a not-to-interfere basis with the main show. Accordingly, he set three stringent standards for diverting effort from the primary theater. First, the leadership must adjudge a secondary theater or line of effort “exceptionally rewarding.” It must promise a massive payoff. But, second, even if such an enterprise had exceptional allure, undertaking it must not place success in the primary theater in jeopardy. Thus—third—commanders should forego lesser pursuits unless they have mustered “decisive superiority” of resources in the primary theater.

    Abjure what matters less! Reward, risk, resources—these are Clausewitz’s Three R’s. For strategy overseers in the Trump administration, it makes little sense to hazard what matters most—US interests in the Western Hemisphere and Indo-Pacific—for the sake of what matters less—US entanglements elsewhere in the world.

• Burden-Sharing Is Vital for America’s National Defense

    Third, the National Defense Strategy designates “burden-sharing” as one of four chief lines of effort, alongside restoring primacy in the Western Hemisphere, deterring China and “supercharging” the defense-industrial complex at home. The strategy’s framers tender tart words for allies that inhabit theaters commanding lesser importance to the US national interest. Here’s the overarching declaration: “As US forces focus on homeland defense and the Indo-Pacific, our allies and partners elsewhere will take primary responsibility for their own defense with critical but more limited support from American forces.” Some close derivative of that phrase, with critical but more limited support from American forces, appears nine times in the document, applied to different regions and allies. The message is clear: We are scaling back.

    Again, this is not an isolationist manifesto. The strategy reassures allies that the United States will still be there for them. At the same time it cautions that the U.S. military will be there to help them help themselves—not to shoulder the burden itself. Washington is shifting the division of labor—and compelling allies, partners and friends to rediscover the international-relations principle of self-help afresh.

If you are unwilling to help yourselves, why should others

    And key US allies boast substantial potential to help themselves. Perhaps the single most striking element of the National Defense Strategy is a simple graphic comparing the combined GDP of NATO-Europe and Canada—in other words, NATO without the US contribution—to that of Russia, the chief threat. The remainder of NATO’s economic and thus latent military, advantage over Russia is colossal, tallying $26 trillion to $2 trillion. The strategy doesn’t say so, but that’s a far heftier economic margin than the United States enjoyed vis-à-vis imperial Japan during World War II.

    Blessed by such a mismatch, the Atlantic alliance can handle its principal antagonist without undue dependence on its American patron. Alliance magnates, member governments and societies merely need to muster the gumption to rally to the common defense.

    Clausewitz would nod knowingly at all of this. The Prussian soldier took a caustic view of alliances and coalitions. After all, he witnessed coalition after coalition dash itself against Revolutionary and Napoleonic France. He took the field as a soldier—and lost ignobly—against the little emperor’s armies, before a final coalition persevered to victory at Waterloo. The central concept in his masterwork On War is a cost-benefit calculus. He proclaims that the “value of the object”—the “object” being a combatant’s political goal or goals—must govern the “magnitude” and “duration” of the campaign it mounts to obtain that goal. The magnitude of the effort is the rate at which the combatant expends militarily relevant resources to obtain that goal and the duration is the amount of time it keeps up the expenditure. How much you want it determines how much you spend on it.

    Magnitude times duration equals the political goals’ total price tag. If a warring society doesn’t covet its goals enough to pay the necessary price, it should decline to take up arms to obtain them. It should refuse to overspend.

    But here’s the rub for alliance warfare. Clausewitz insists that one ally fighting on another’s behalf tends to commit itself only tepidly to the cause. Applying his value-of-the-object formula, an external ally assigns the common goal only modest importance. It’s peripheral. A halfhearted ally sends a middling military contingent to uphold its alliance obligations and it withdraws from the enterprise when the going gets tough. Clausewitzian skepticism toward alliances applies doubly to regions that one ally deems secondary in importance to its national interests and purposes as the leadership construes them.

    Hence the discomfiture within NATO today, over seeing Europe demoted to third priority after the Western Hemisphere and the Indo-Pacific. Conceivably the United States could entertain only a middling commitment to European security after over a century of rating the European rimland tops on the US strategic to-do list. This marks wrenching change.

• The NDS Prepares America to Take on China

    And lastly, to shift gears abruptly, plaudits to the National Defense Strategy’s framers for reiterating their approach to deterring China. They declare that, “As the NSS directs, we will erect a strong denial defense along the First Island Chain.” That means combining marine geography, alliance relations and military power to transform the island chain—which meanders southward from Japan, through Taiwan at its midpoint, through the Philippine archipelago and on toward the Strait of Malacca—into what, ahem, some many years ago started calling a “Great Wall in reverse,” a barrier to Chinese military and commercial movement. Land-, air- and sea-based firepower positioned along the island chain imprisons shipping and aircraft within the China seas while encumbering north-south movement along the Asian seaboard.

    We think of access denial as a Chinese thing, but the logic of access denial works both ways. It hands Asian allies and their U.S. supporters options. First-island-chain defense would pinch China’s access to critical maritime trading regions, bringing the economic hurt, while at the same time inhibiting the People’s Liberation Army’s efforts to combine forces within the China seas and barring China’s navy and air force access to the vast maneuver space that is the Pacific high seas. Missile-armed troops operating with ships in surrounding waters and aircraft overhead could close the straits traversing the island chain. The allies and their US backers would convincingly menace China with a very bad day in wartime—and thus pose a daunting deterrent in peacetime. Enjoy that.

    Walls have cognitive as well as military impact.

    In short, hard realities are reasserting themselves in this age of bareknuckles strategic competition. The National Defense Strategy prescribes a defensible, if contestable, approach to coping with them. Let the debate proceed.