During his prosperous 2024 U.S. presidential campaign, Donald Trump assured voters that he would end the wars in Ukraine and Gaza, perhaps even before taking office. But both conflicts dragged on at great human cost, and diplomacy proceeded only in fits and starts. Nine months into his presidency, Trump finally brokered a cease-fire between Israel and Hamas-but only after presiding over the breakdown of the truce he inherited from President Joe Biden and an escalating humanitarian crisis in Gaza. The war in Ukraine, meanwhile, continues unabated.
These challenges are not unique to Trump; they bedeviled Biden, too. Indeed, the difficulty of bringing both wars to an end illustrates the strategic dilemmas facing the United States in managing a small but critical subset of its partners: so-called quasi allies. Quasi allies-which, since the end of World War II, the United States has cultivated as it has built its alliance system-are more than partners but less than treaty allies.They have special status in Washington, but they lack the feature of an alliance that matters moast: a formal U.S.security guarantee.
The recent wars in Ukraine and the Middle East have put quasi allies at the center of U.S. foreign policy. The United States has supported Ukraine in resisting Russia’s attempt at subjugation,sending billions of dollars’ worth of advanced weaponry to its armed forces. Ukraine has maintained its sovereignty and political independence, whereas Russia has suffered more than a million military casualties and significant materiel losses-results achieved without direct conflict between Moscow and Washington. In the Middle east, the United States has enabled an Israeli-led campaign that set back Iran’s nuclear program and broke its regional network of armed proxy groups, even as those operations also deepened the humanitarian catastrophe in Gaza. This record points to the advantages of supporting strong quasi allies at the frontlines of geopolitics: these relationships allow the United States to advance its interests in consequential regions through indirect, less costly means.
But the United States’ attempts to manage its role in these wars have also highlighted strategic dilemmas endemic to quasi alliances and notably pronounced in wartime.If Trump is to fulfill his goal of bringing peace to the Middle East and Europe, his governance needs to better manage these dilemmas. And Washington’s experience with ukraine and Israel should inform planning for a high-stakes contingency involving Taiwan, another quasi ally in a perilous neighborhood.
More Than Friends
Within its vast network of relationships around the globe, the United States categorizes most of its friends as either allies or partners. Washington is bound to its allies by legally codified treaties featuring mutual defense clauses. This pledge that an attack on one is an attack on all backstops allies’ security and extends the U.S. nuclear umbrella. Partners, by contrast, may receive security assistance from the United States but do not presume that the U.S. military would come to their aid if they were attacked.
Quasi allies represent an awkward third category. These are states through which the United States sees opportunities to advance its interests. They may receive significant military training and assistance, host a large U.S. troop presence, and coordinate closely with washington. Some even enjoy a confusing designation,conferred by the president, as a “major non-NATO ally,” which does not entail a security commitment. And unlike partners, the scope and scale of Washington’s investment in their security creates ambiguity around whether and to what extent the United States would intervene to defend quasi allies if they were attacked. Indeed, the United States has occasionally come to the defense of its quasi allies, as when it helped Israel defeat Iranian aerial attacks twice in 2024 and again during the Iran-Israel war in June. But there tend to be good reasons why the United States stops short of extending the kind of mutual defense commitment that would cement a treaty alliance-including concerns about becoming entangled in a turbulent region, provoking an adversary, or pledging to defend a partner that may not pursue Washington’s preferred policies. This ambiguity makes quasi alliances weaker tools of deterrence and reassurance than formal alliances, and it helps explain why quasi allies are more vulnerable to external aggression than treaty allies.
Despiteparried Netanyahu’s request for U.S. military participation in the strike by arguing that it would trigger a regional firestorm at a time when Israel was ill prepared for a multifront war. In April 2024, after Iran launched its first aerial attack on Israel, Biden told Netanyahu that the United States would not support an Israeli counterattack against iran, urging him to take the unsuccessful nature of the Iranian salvo as a win, thanks to joint defensive operations. Netanyahu partially accepted this advice, hitting a strategic air defense site inside Iran without claiming public credit for the strike.
when Trump took office,he clearly signaled a strong preference to address Iran’s nuclear program via diplomatic means. Israel still launched a military campaign against Iran. The fact that only the U.S. military had bombs capable of penetrating Iran’s nuclear facilities meant that Netanyahu was betting on Washington’s ultimate involvement, a gamble that paid off in June, when Trump authorized U.S.strikes. Of all the points on which interests diverge between the United States and its quasi allies, escalation and risk tolerance are the highest-stakes areas because the danger of entanglement is the greatest.
The Limits of Leverage
If relative power and material dependence translated neatly into influence, the United States would have overwhelming leverage over its quasi allies, resulting in an ability to manage tension through coercive means, such as withholding weapons, and to dictate wartime decisions. But the reality is more complicated. The relationship between the United States and its quasi ally is itself a center of gravity, especially during wartime: if the relationship frays, the break advantages the adversary.
When quasi allies fight enduring wars, the most effective way for the United States to secure its desired outcome is either to help its partner win the war outright or to convince the adversary that support will continue to flow until a favorable negotiated settlement is reached. These dynamics make it challenging to withhold vital military support as leverage in shaping how a quasi ally fights and what peace it will accept.And it makes wars involving support to quasi allies challenging to end.In his bid to end the war in UkraineTrump calculated that Ukraine’s dependence on the United States meant that he could browbeat Kyiv into a negotiated settlement that heavily favored moscow. trump tested this hypothesis by publicly berating Zelensky in the Oval Office, then cutting off military and intelligence assistance. Rather than coercing Ukraine into war-ending concessions, however, this gambit only spotlighted the frailty of the bonds between kyiv and Washington under the Trump administration and led the Kremlin to double down on its strategy of diplomatic recalcitrance and intensified military pressure.
biden took the opposite approach. In 2022, the United States and its G-7 allies declared their intent to support Ukraine for “as long as it takes.” This commitment and the consistent support that followed bolstered Ukraine’s will to fight and telegraphed that time was not on Russia’s side. But it obscured two difficult realities: that Congress would not indefinitely sustain billions of dollars in support to Ukraine and that ending the war would inevitably require pressuring Kyiv to step back from its unattainable near-term objective to restore its pre-invasion border.
Washington needs better answers to these strategic dilemmas.
The united States’ efforts to use its leverage to moderate Israel’s maximalist war aims and to end the war in Gaza were always fraught and only grew more so as the humanitarian calamity in Gaza deepened. The Biden administration continually wrestled with the question of whether and how to condition military support to Israel at a time when Israel remained under threat from Iran and Hezbollah. It came closest to doing so in May 2024,in anticipation of major Israeli military operations in Rafah. Concerned that this move would endanger nearly a million civilians and undermine prospects for a cease-fire,Biden proclaimed he would not supply the weapons for the offensive and paused the delivery of 2,000-pound bombs. Biden officials ultimately succeeded in persuading Israel to downscale its Rafah operation, one of several modest successes in using pressure to improve humanitarian outcomes in Gaza, and never resumed the delivery of 2,000-pound bombs. But the administration’s concern about l