It has taken the Trump administration just two months to race through all five years of the Johnson administration’s Vietnam policy: entry, escalation, frustrated stalemate, and negotiations. Now, it’s on the Nixon administration’s turf: first blustery threats, then gradual realization of the need to extricate via an unsatisfying deal. If this pace holds, the intervention in Iran should be over in another few months, by which point the recriminations will already have begun.

Of course, no historical analogies are perfect, and there are many obvious differences between the conflicts in Iran and Vietnam: different regions, different ideologies at play, a much shorter time frame, no U.S. ground troops or draft, no change in administrations, advanced military technology, and more. Still, there are notable symmetries in the structures of the two conflicts. And the same is true of the war in Ukraine, which has a structure symmetrical to that of the Korean War. And because structures constrain policymakers’ choices, recognizing these patterns provides clues to how the wars will end.

The U.S.-Israeli war on Iran is likely to conclude like the Vietnam War did in 1973, with an unstable compromise settlement that addresses some issues but leaves other important ones unresolved. Just as the ultimate fate of South Vietnam was left to be determined later, the ultimate fate of the Islamic Republic and its nuclear program will be left for another day. In contrast, the war in Ukraine, like the Korean War, will probably end with a settlement that solidifies something like the current line of conflict, with frozen borders patrolled indefinitely in an armistice that proves more stable and durable than most observers expect.

HALF THE WAY WITH LBJ

In November 1963, the leaders of both South Vietnam and the United States were assassinated, putting President Lyndon Johnson suddenly in charge of two countries in crisis. In Vietnam, motivated and well-led northern forces, together with their guerrilla associates in the south, were steadily gaining ground against a hapless South Vietnamese regime. Unless Washington did something to reverse the trend, it seemed Saigon would eventually fall, and the country would be reunified under communist control. Johnson and his team were not greatly optimistic about winning the war, but they feared the domestic and international consequences of losing it. So they decided to increase support for Saigon in hopes that a show of force would cause Hanoi to back off.

At first, this meant sending economic aid and military advisers. Then it meant bombing. Then it meant sending ground troops. And then it meant more of everything. Yet Hanoi stuck to its core objectives and refused to give in. By 1968, the war was costing so much blood and treasure and causing such domestic turmoil that Washington started looking for a way out. Johnson himself never accepted defeat, but he capped the war’s escalation, declared a unilateral halt to the bombing, withdrew from political life, and passed the problem on to his successor.

That turned out to be Richard Nixon, who, with his national security adviser, Henry Kissinger, inherited a fundamental imperative to finish the war but little political capital for new ventures. Neither Nixon nor Kissinger ever contemplated simply abandoning Saigon, but they had their sights set on remaking superpower relations and understood the United States had to move on relatively soon—certainly before the next presidential election. At first, they tried to achieve old goals through a new mixture of force and bluff. They hoped that the North Vietnamese could be cowed by savage new bombing and wild threats, the Soviet Union and China could be cajoled into helping, and the American public could be pacified with small troop reductions—and that all this together would produce an agreement allowing American withdrawal, South Vietnamese survival, and North Vietnamese disengagement. This was the period White House Chief of Staff H. R. Haldeman later immortalized in his memoirs:

[Nixon] was certain he could force the North Vietnamese—at long last—into legitimate peace negotiations. The threat was the........

© Foreign Affairs