Iraq is collapsing as a country. This week's bombings in Baghdad, killing more than 90 people, were just one more reminder that the place remains deeply unstable and violent.
There is a lesson to be drawn from this, one that is still resisted by many powerful people in Washington.
As Iraq has spiraled downward, policymakers have been quick to provide advice.
Perennial hawks like Sen. John McCain have argued that if only the Obama administration would send more troops to the region, the place would be more stable. Others say we need more diplomats and political advisers who can buttress military efforts.
Still others tell us to focus on the Iraqi leadership and get them to be more inclusive.
Perhaps it is worth stepping back from Iraq and looking at another country where America has been involved. The United States has been engaged in Afghanistan militarily, politically and economically for 15 years.
It had many "surges" of troops. It has spent more than $1 trillion on the war, by some estimates, and still pays a large portion of Afghanistan's defense budget. Afghanistan has an elected government of national unity.
And yet, last October, the United Nations concluded that the insurgency had spread to more places in the country than at any point since 2001. Danielle Moylan reports in The New York Times that the Taliban now control or contest all but three districts in Helmand province.
She adds that 36,000 police officers — almost a quarter of the force — are believed to have deserted the ranks last year. And last month, the Taliban penetrated Kabul itself, attacking a building run by the National Directorate of Security, which is responsible for much of the security in the capital, as The New Yorker's Dexter Filkins has reported.
Some argue that 15 years is not enough. They point to South Korea and Germany and say that the United States should simply stay unendingly. I am not opposed to a longer-term U.S. presence in Afghanistan, especially since the country's elected government seems to want it.
But the analogy is misplaced. In Germany and South Korea, American forces remained to deter a foreign threat. They were not engaged in a never-ending battle within the country to help the government gain control over its own people.
The more appropriate analogy is Vietnam.
Much has been made recently of a pair of interviews on American foreign policy, one with President Obama, the other with one of his closest aides, Ben Rhodes. Both men have been described as arrogant, self-serving and brimming with contempt for the foreign policy establishment.
Certainly, as most administrations would, Obama and Rhodes sought to present their actions in a positive light. So Obama congratulates himself for stepping back from the edge of military intervention in Syria. He never grapples with the fact that his own careless rhetoric — about Bashar Assad's fate and red lines — pushed Washington to the edge in the first place.
But on the most important issue of substance, Obama is right and his critics are wrong. The chief lesson for American foreign policy the last 15 years is that it is much easier to defeat a military opponent in the greater Middle East than to establish political order in these troubled lands.
The mantra persists in Washington that Obama has "overlearned" the lessons of Iraq. But the lessons come not just from Iraq. In Iraq, Afghanistan, and Libya, it took weeks to defeat the old regime.
But years later, despite different approaches, all these countries remain in chaos. Can anyone seriously argue that a few more troops, or a slightly different strategy, would have created stability and peace?
The Obama administration's policy is trying to battle the Islamic State and yet steer clear of anything that would lead it to occupy and control lands in the region. I worry that the U.S. is veering toward too much involvement, which will leave Washington holding the bag, but I understand the balance the administration is trying to strike.
In Syria, Washington's real dilemma would be if the effort worked and the Islamic State were defeated. This would result in a collapse of authority in large swaths of Iraq and Syria that are teeming with radicalized Sunnis who refuse to accept the authority of Baghdad or Damascus.
Having led the fight, Washington would be forced to assert control over the territory, set up prisons to house thousands of Islamic State fighters, and provide security and economic assistance for the population while fighting the inevitable insurgency.
You know you're in trouble when success produces more problems than failure.
Fareed Zakaria hosts CNN's "Fareed Zakaria GPS," and makes regular appearances on shows such as ABC's "This Week" and NBC's "Meet The Press." He has been an editor at large Time magazine since 2010, and spent 10 years overseeing Newsweek's foreign editions. He is a Washington Post (and internationally syndicated) columnist. He is author of: "The Post-American World." For more of Fareed Zakaria's reports, Go Here Now.