Cartoon by Patrick Chappatte

How to Tell if You’re in a Good Alliance

By Stephen M. Walt

Foreign Policy: Both liberal and conservative critics of Donald Trump’s foreign policy believe that the U.S. president has done enormous damage to America’s array of global alliances. It’s easy to understand why: Trump has repeatedly questioned the value of NATO; picked senseless fights with democratic leaders in Europe, Asia, and North America; and, more recently and controversially, betrayed the Kurds.

The Economist believes the damage “will take years to mend” and warns darkly that “these concerns represent the unravelling of the order that America worked hard to build and sustain in the decades since the second world war.”

Crucial to this indictment is a rarely examined assumption: the belief that every one of the United States’ current commitments is a vital national asset and that all its present allies and partners are equally deserving of steadfast U.S. support. But surely this is not the case, for not all allies are created equal, and the value of any commitment is likely to wax or wane over time.

To be sure, having the right allies can be extremely valuable in some circumstances. During the Cold War, for example, the U.S. alliance network exceeded (and in economic terms, dwarfed) the Soviet bloc in population, gross national product, total military manpower, and annual defense spending. The combined strength of the U.S. alliance network is not the only reason the United States triumphed over its Soviet adversary, but it certainly helped. Looking ahead, it is hard to see how the United States could balance a rising China and limit Beijing’s capacity to project power around the world without close and effective partnerships with a number of countries, especially in Asia.

Alliances are not an unalloyed good, however, because they also involve costs and obligations. Depending on the precise nature of the commitment, alliances may create new military missions and thus increase one’s defense requirements—especially if the ally is far away or hard to defend—and alliance obligations may constrain a country’s foreign-policy autonomy in other ways. The Obama administration was reportedly reluctant to confront Saudi Arabia over its conduct in Yemen, for example, because it feared doing additional damage to a relationship already strained by the nuclear deal with Iran. Sometimes, even allies of long standing can become more trouble than they are worth.

For this reason, wise countries choose their allies carefully and do not treat any of them as sacred or inviolable—no matter how ardently leaders defend the relationship in public. As the writers Doug Bandow and Christopher Preble recently reminded us, an alliance is merely a means to an end (typically greater security) and not an end in itself. Unfortunately, U.S. foreign-policy pundits all too often fetishize nearly all of America’s current partnerships—both formal alliances such as NATO and less formal security arrangements with dozens of other countries—implying that any diminution in these ties constitutes a dangerous waning of U.S. “influence.”

Which brings us to the obvious question: What makes for a good ally? What are the qualities that make a foreign power an especially valuable partner and therefore justifies a U.S. security commitment?

Here’s a quick list for you to ponder.

Ideally, a good ally is economically strong and military capable, or it controls other strategic assets such as natural resources or a key strategic location, so that it can contribute meaningfully to the overall strength of the alliance. As noted above, the United States won the Cold War in part because it had powerful, wealthy, and militarily capable states such as Japan, Germany, France, and the United Kingdom on its side, while the Soviet Union only had help from relatively weak and captive satellites in Eastern Europe or overseas dependencies such as South Yemen and Ethiopia. (NATO’s European members have let their defense capabilities atrophy badly in recent decades, but they had impressive military forces during most of the Cold War.) North Vietnam was a better partner for Moscow than South Vietnam was for Washington, but on the whole, the U.S. alliance system was much stronger than theirs.

A good ally is politically stable, so that you don’t need to spend a lot of time or money propping it up or trying to make sure its internal politics don’t go south. And other things being equal, a good ally is not so vulnerable that defending it is almost impossible. Obviously, a state that faces no external dangers has little need for allies, but, ideally, one should prefer allies that aren’t about to collapse or in constant danger of being overrun.

Almost by definition, a good ally has interests that are roughly compatible with one’s own. For example, the United States does not want any single power to dominate the oil-rich Persian Gulf, and—guess what?—neither does any of its partners there. No two states have identical interests, but the more that interests diverge, the less valuable or viable an alliance will be. As I’ve noted previously, that is why the U.S. partnership with Syrian Kurdish forces was bound to end eventually. The United States joined forces to destroy the Islamic State’s so-called caliphate, and once that task was accomplished, the U.S. commitment was bound to wane.

If interests diverge sufficiently, an alliance will become irrelevant and moribund and may even turn into a serious rivalry. The United States backed Saddam Hussein during the Iran-Iraq War only to turn against him when that war ended and Iraq turned on Kuwait and seemed bent on dominating the Persian Gulf. Similarly, the United States and China were tacit allies against the USSR during the 1970s, but China’s rise and the Soviet collapse have brought a steady rise in Sino-American tensions  >>>

Stephen M. Walt is the Robert and Renée Belfer professor of international relations at Harvard University.