A country that acts solely out of goodness and duty is bound to be played; the world is simply too nasty, too mean a place for the well-intended naive, and even a good country will often have to make ugly decisions that are hard to sleep on. However, this shouldn’t be taken to mean that acting in our self-interest is necessarily in opposition to good morals. More often than not, the smart thing to do overlaps with the right thing to do.

During the occupation of Iraq, many Iraqis decided to throw their lot in with the American-led coalition and the new Iraqi government. Whatever, their reasons, it was a risky and — in some cases — very brave decision to make. Though many paid for it with their lives during the insurgencies that rocked the country before its precarious stabilization in 2008, it seemed to have been the right one to make. But in the provinces that have fallen to the Islamic State since our decision to leave, it’s again become sentence to torture and death:

As members of the police, or suspected of ties to the Iraqi government or the United States, the men were beaten and tortured by militants during their captivity [before being rescued by Kurdish and American forces last week] …

Told by his Islamic State guards he was just hours away from execution, Saad Khalif Ali Faraj, a 32-year-old police officer, said he had spent his last night in captivity writing a letter to a nephew, urging him not to risk his safety by going searching for him.

“I told him: ‘Look after your brothers and your family,’ ” he recalled. “‘Don’t go out looking for me. They will kill me. Do not look for me.’”

In a two-and-a-half-hour interview at a government building in the town of Salahaddin in Iraqi Kurdistan, the former prisoners, all Sunni Muslims, gave accounts that illuminated life and punishment in one of the Iraqi areas long ago captured by the Islamic State…

The militants were wary of anybody who had served in the Iraqi police or army, or whom they thought might have had contact with Americans or Kurds.

… Mr. Jibouri’s troubles began when his younger brother, who had taught English in Hawija, came under suspicion, was imprisoned and told he would be killed. He escaped, but the Islamic State exacted retribution by detaining Mr. Jibouri, three of his other brothers, his cousins and his 80-year-old father.

After a week, all but one of them was set free. The exception was an older brother who was killed as a warning to the family.

“They executed him in cold blood,” Mr. Jibouri said as he covered his face and sobbed.

The family was warned never to mention the killing, but soon the militants came looking for Mr. Jibouri and his remaining brothers again. After confiscating Mr. Jibouri’s cellphone, the militants discovered two contact numbers for two American soldiers who had worked with the Iraqi police in Hawija in 2008.

Mr. Jibouri denied that he had any lingering ties to the United States military, but that simply led to more beatings and torture.

“If I say ‘yes,’ they will execute me. If I say ‘no,’ they will hit me to say ‘yes’ to execute me,” he explained.

Bear in mind that Faraj and Jobouri were not rescued not because of their past work with the United States, but out of the sheer luck of being mistaken for pesh merga fighters during one of the handful of ground operations we’ve launched in the past year. Had they not been — against all odds — in the right place at the right time, they’d be dead and that would have be consistent with our policy of not giving a fig for those like him who helped us. Amazingly, the guy’s grateful:

Mr. Jibouri asked if he could send a message to an American audience: He said he was grateful to the United States and to Joshua L. Wheeler, the Army Delta Force master sergeant who was killed in the rescue. “May God keep him in heaven,” he said.

“Self interest” is often used as a synonym for selfishness and license, but it shouldn’t be. If we don’t get to work on time and produce, we get fired; if we treat our loved ones badly, they leave us; act like a jerk to our acquaintances, and we find ourselves friendless just when we need the help.

American foreign policy can’t be based on charity or goodness; it won’t work. But where our interests are consistent with our morals, we should act with speed and decision. Leaving people like Jibouri and Faraj to ISIS’s sadists — or allowing the doctor who helped us catch bin Laden to languish in Pakistani prison for another decade — tells the world that when the Americans ask for your assistance, the smart move lies somewhere between feigning stupidity and outright betrayal. It’s hard enough to get a man to pledge his life, fortune, and sacred honor for his own cause, let alone ours.

We should never fall into the trap of relying on our national honor — that leads to its own trouble — but we should value and cultivate it if we ever want to be helped again by people of influence and intelligence. It’s in our interest.