In a world where great-power competition is intensifying, a revealing test of foreign-policy acumen is a country’s ability to avoid costly conflicts or other endeavors that waste resources, divert attention, and ultimately leave them weaker rather than stronger. In other words: staying out of quagmires. Great powers are often happy to see their rivals stumble into strategic quicksand and may even try to encourage such developments, but wise leaders try to stay out of this kind of trouble.

In recent decades, China has done a far better job of avoiding quagmires than either the United States or Russia. Post-Cold War hubris led U.S. leaders to take on a vast array of global responsibilities, some that made sense but many that did not. The “forever wars” in Iraq and Afghanistan are the most obvious examples of the latter, of course, but the United States also gotten itself mired in lesser conflicts in Libya, Yemen, Syria, and various parts of Africa, largely as part of the “global war on terror.”

One might add the long, inept, and fruitless effort to broker an Israeli-Palestinian peace, which consumed vast amounts of presidential time and attention and ultimately failed, in good part because Washington acted not as a fair-minded mediator but as “Israel’s lawyer.” And now U.S. President Donald Trump has walked open-eyed into a quagmire of his own making with Iran, one with few if any benefits, increasingly obvious costs, and no obvious exit save a humiliating retreat.

Similarly, since 2000, Russia has engaged in a series of frozen conflicts with various neighbors, failed to prop up clients such as former Ukrainian President Viktor Yanukovych or former Syrian leader Bashar al-Assad, and is now mired the running sore of war in Ukraine. Not only have these actions cost the Russian economy and the Russian people a great deal, but they have also poisoned relations with most of Europe and made Russia increasingly dependent on China.

Both Washington and Moscow had reasons for acting as they did, but it is hard to argue that these various adventures left either country in a stronger global position.

By contrast, China has stayed out of costly quagmires and focused on building power at home, constructing islands in the South China Sea, expanding its diplomatic presence and influence abroad, insulating itself from foreign pressure by building up stockpiles and reserves, and gaining leverage through its control of raw earths and other parts of global supply chains. To be sure, its growing military power and increasingly assertive foreign policy have alarmed its neighbors and encouraged them to balance against Beijing, but its overall position vis-à-vis both Russia and the United States has improved considerably. China’s approach suggests that staying out of trouble abroad is a pretty smart strategy.

So why do states blunder into quagmires, and how might they avoid them in the future? Here are some of the warning signs.

Ignorance. Nobody starts a war that they think will be long, costly, and maybe end with being defeated. It follows that if they had known in advance what they were getting into, most leaders would have tried something else.

And that suggests that quagmires usually arise from ignorance about the country you’re taking on, the difficulties you will encounter against them, or the ways that other actors will respond. The lesson: If you’re about to intervene in a country that you know very little about, look out.

Bad advice. Decisions to intervene don’t arise from thin air; somebody has to come up with the idea and then convince the people in charge to embrace it. If you want to avoid a quagmire, therefore, you should be deeply skeptical of the advice you’ll get from self-interested parties who have their own reasons for wanting you to intervene.

It was a mistake for the Bush administration to listen to pro-war Iraqi exiles such as Ahmed Chalabi, who wanted to ride to power on the back of the U.S. military. It was equally foolish for Trump to believe Israeli Prime Minister Benjamin Netanyahu’s sales pitch for a war with Iran, or to have paid attention to similar blandishments from pro-war voices in the United States.

This problem is nothing new. In his Discourses on Livy, Niccolò Machiavelli specifically warns leaders against taking the testimony of self-interested parties (in his case, exiles) too seriously:

“How vain the faith and promises of men are who are exiles from their own country. … Such is their extreme desire to return to their homes that they naturally believe many things that are not true, and add many others on purpose; so that, with what they really believe and what they say they believe, they will fill you with hopes to that degree that if you attempt to act upon them, you will incur a fruitless expense, or engage in an undertaking that will involve you in ruin.”

Notice that the first two problems reinforce each other. The more ignorant one is, the greater the tendency to accept the advice of those who claim to know what is going on.

Groupthink. States are also more likely to stumble into quagmires when options aren’t debated in a clear and fair-minded way. Overconfident autocrats surrounded by sycophants and loyalists (think Russian President Vladimir Putin or Trump) are prone to making mistakes of this kind, but so are leaders who refuse to listen to dissenting views and are prone to ignoring information that doesn’t fit their preconceived notions.

We all have a tendency to overvalue evidence that supports what we want to do and to discount evidence that we’re wrong, which is why leaders seeking to avoid a quagmire should work overtime to hear alternative views and encourage advisors to stress-test the assumptions underlying the case for war. When leaders don’t do this, the combination of ignorance, bad advice, and a biased decision-making process can lead directly to…

Overconfidence. Ignorance and bad advice typically combine to persuade decision-makers that success will be easy to achieve, either because the opponent is militarily inferior, its government is fragile and will quickly collapse, the local population is restive and will welcome the invader, or some combination of the above. Sometimes these things are true, but not often, and managing the aftermath of victory can be even more challenging than the purely military task of defeating an inferior foe.

If you want to avoid a quagmire, therefore, make sure you have carefully considered what you are going to do if you win. Even more important, make sure you have a Plan B if your best-case theory of victory turns out to be wrong and you find yourself facing a protracted fight.

Unreliable local partners. The U.S. experience in Vietnam, Afghanistan, Iraq, and now Iran teach a similar lesson: Quagmires are hard to avoid when you don’t have competent and reliable local partners. Washington devoted vast sums trying to nation-build in the first three cases, but its local clients were divided, corrupt, and had their own agendas. Trump seems to have believed that unhappy Iranians (of which there are many) would rise up if the regime’s top leaders were gone, a fantasy that entirely ignored the regime’s well-organized security forces and the lack of a well-organized opposition.

Putin made a similar miscalculation in thinking that the Ukrainian government would dissolve as soon as his forces crossed the border (or be easily replaced by pro-Russian quislings once the invading force reached Kyiv), a vain hope that revealed his failure to appreciate the intensity of Ukrainian national feeling.

Once it is clear that the optimistic prewar expectations were false and that the war will be long and difficult, a new set of problems comes into play. Even if the smart thing to do is to cut one’s losses and disengage, there are at least two obvious reasons why leaders often find it difficult to extricate themselves from a costly quagmire.

Credibility concerns. Governments often believe that they must “stay the course” to preserve a reputation for steadfastness and reliability. Former U.S. Secretary of State Henry Kissinger knew the United States couldn’t win in Vietnam, for example, and even conceded that it might have been better if the United States had never entered the war. But he insisted that the commitment of 500,000 U.S. troops had “settled the issue of the importance of” Vietnam because he believed—incorrectly—that withdrawing would undermine U.S. credibility and cause other allies to abandon Washington. He knew the war was lost and that Vietnam was of marginal strategic importance, but his obsession with credibility helped prolong the war for six more years.

And as Daniel Ellsberg argued in a famous essay, there is a domestic political analogue here. Leaders are often reluctant to extricate themselves from quagmires because they fear the domestic political consequences of an obvious failure. Even when they know that victory is unlikely, they prefer to kick the can down the road and hand the problem off to their successor. U.S. President Lyndon Johnson passed Vietnam on to Richard Nixon, and Presidents George W. Bush, Barack Obama, and Trump each bequeathed Afghanistan to the person who replaced them. President Joe Biden had the courage to end a war that he understood the United States was unlikely to win but was widely criticized for the (inevitably) chaotic outcome that accompanied the U.S. withdrawal.

This may also be why Trump won’t simply cut his losses and end the war with Iran: He’s still hoping that he can achieve something he might be able to package as a “victory.” Good luck with that.

Ironically, this fear of domestic political consequences may be misplaced. Saddam Hussein ended the foolish war that he had started with Iran after eight years of fighting and didn’t fall from power, and he remained in charge in Iraq even after his humiliating defeat in the first Gulf War. President Ronald Reagan withdrew from Lebanon after more than 240 U.S. service members were killed in a terrorist bombing, but he was still widely regarded as a tough-minded, hawkish president. Even Biden suffered little long-term damage from disengaging from Afghanistan in his first year in office—that early decision played hardly any role in the 2024 campaign or in Kamala Harris’s subsequent loss.

“Victory is just around the corner.” Powerful states also remain stuck in quagmires because they can afford to keep fighting, and because they have the wherewithal to keep trying new approaches.

“There’s a lot of ruin in a nation,” wrote Adam Smith, and that’s especially true for countries with large populations and large economies. Even when the stakes are not that great and victory seems unlikely, a great power can keep a dumb war going for a long time, especially if it can rely on an all-volunteer force, run deficits instead of raising taxes, and keep trying new strategies or new weapons in the hope that one of them will provide the key to victory. Look at all the different things that Russia (and Ukraine) have tried over the past four years, or the various options and strategic innovations that the United States attempted during the various quagmires that it has stumbled into.

Thus, Americans were repeatedly told that they had “turned the corner” in Vietnam, a mantra that was resurrected and repeated in Iraq and Afghanistan. In the former, Washington tried coercive bombing, an invasion of Cambodia, mining North Vietnamese harbors, widespread use of defoliants such as Agent Orange, the construction of “strategic hamlets” to protect the local population, “Vietnamization,” etc., all to no avail. The 2007 “surge” in Iraq brought some short-term military benefits but failed to resolve the country’s broader political problems, and the analogous Afghanistan “surge” that the Pentagon foisted on Obama in 2009 was equally unsuccessful. Wealthy states can keep trying different options for a long time, and it is always at least remotely possible that a bit more effort will yield success. Upon such hopes are quagmires prolonged.

The bottom line is that quagmires occur because getting out of a war is harder than getting into one. If one wants to avoid quagmires, therefore, a deep-seated reluctance to get involved in foreign wars is one’s best protection. States still need capable military forces and a population that is willing to fight to defend truly vital interests, but pursuing wars of choice fought for flimsy or marginal reasons, on the assumption that they will be easy, is a good way to find yourself in conflicts that you can neither win nor easily end. Thus far, Chinese President Xi Jinping and his associates seem to understand this principle better than Trump and many of his predecessors. As long as that remains the case, advantage Beijing.