WASHINGTON — The United States helped protect the last Middle Eastern tyrant thought to use chemical weapons.

That dictator was Iraq’s Saddam Hussein. Because he was fighting Iran in the 1980s, the Reagan administration fed him secret intelligence. And because his country bought U.S. crops, farm-state politicians fought off sanctions.

Now, amid allegations of chemical weapons use by Syria, the Obama administration is preparing a case for military action. Moral assertions will be paramount, as in Secretary of State John Kerry’s declaration Monday that “our sense of basic humanity is offended.”

History, though, offers a harsher perspective. From Iraq and Syria, to Rwanda and Armenia, morality as a motive in U.S. foreign policy is more contingent than absolute.

“It’s quite selective. The government knew of the fact that Iraq was using chemical weapons, and did not deter them,” Joyce Battle, an analyst at the National Security Archive, a nonpartisan research center, said in an interview Tuesday. “But when it’s thought to be in U.S. interests, the government will adopt a moralistic stand when it wants to justify its policies.”

Put another way, foreign policy calculations are invariably cold-blooded, notwithstanding moral declarations. Stirring words can be worn like a new cloak during a campaign, then set aside for action.

The perennial Armenian genocide resolution conflict showcases how this works.

Presidential candidates invariably declare to Armenian-American audiences that they will formally recognize as genocide the slaughter that took place in the Ottoman Empire between 1915 and 1923. Samantha Power, a foreign policy adviser to candidate Barack Obama in 2008, made this campaign-season pledge back then on Obama’s behalf.

“He’s a true friend of the Armenian people,” Power assured Armenian-Americans in an early 2008 video, calling Obama an “acknowledger of the history” who would have a “willingness as president to commemorate it.”

Once in office, though, Obama followed the urgings of military and diplomatic leaders who cautioned against alienating Turkey, a crucial U.S. ally. Obama has since refused to use the word “genocide” in his annual Armenian statements. Power now serves as the Obama administration’s United Nations ambassador.

The inconstant U.S. response to allegations of Middle Eastern chemical weapons use further underscores how morality comes and goes.

Kerry, in his remarks Monday, asserted it was “undeniable” that the Syrian military had used chemical weapons on a Damascus suburb. The Britain-based Syrian Observatory for Human Rights and Doctors Without Borders put the death toll at at least 300 people. While not publicly endorsing a casualty total other than to say that it was on a “staggering scale,” Kerry declared with black-and-white certainty, “There must be accountability for those who would use the world’s most heinous weapons.”

The United States took a different approach in the 1980s, when the Reagan and George H.W. Bush administrations publicly denounced Iraq’s chemical weapon use, but stopped short of firmer action.

“They still thought Saddam Hussein was somebody they could work with,” former California Rep. Howard Berman, a strong advocate of sanctions against Iraq, recalled in an interview Tuesday. “They still had not stopped their tilt toward Iraq.”

A Nov. 1, 1983, State Department memo unearthed by Battle of the National Security Archive noted that “we have recently received additional information confirming Iraqi use of chemical weapons.” The 1983 memo also hinted at potential Iraqi motives for using the widely reviled weapons, observing that “Iraq is at a disadvantage in its war of attrition with Iran.”

Hoping to constrain Iran, the Reagan administration provided what Battle called “quite extensive” military intelligence to Iraq during parts of the 1980-88 war between the Middle East neighbors. Citing CIA documents and interviews, Foreign Policy magazine reported this week that “the Iraqis used mustard gas and sarin prior to four major offensives in early 1988 that relied on U.S. satellite imagery, maps and other intelligence.”

Members of Congress, too, would publicly chide Iraq over chemical weapons, while fighting against more vigorous action that might impinge on U.S. businesses, as when farm-state lawmakers in 1990 challenged efforts to stop Iraq’s use of U.S. credit guarantees to buy U.S. farm products.

“I understand the blood pressure behind this,” Republican Pat Roberts, now a Kansas senator but then a member of the House of Representatives, said during one 1990 House debate. But he added, “We do sell to Iraq about a million tons of wheat and 450,000 tons of rice, [so] I wonder who we’re hurting here.”

Five days after that House debate, Iraq invaded Kuwait, and Congress and the White House changed their tune.

The African nation of Rwanda provides one of the most heart-wrenching examples of cold-blooded national calculations.

More than half a million people were slaughtered in Rwanda during a three-and-a-half-month bloodbath that started in April 1994. The Clinton administration remained aloof during the genocide that targeted the Tutsi. Politically, officials were wary about additional U.S. casualties in the year after the deaths of 18 U.S. soldiers in Somalia. Bureaucratically, they were leery about making a commitment, as when Defense Department officials in a May 1, 1994, memo cautioned against use of the word “genocide.”

“Be careful,” stated the memo, obtained under the Freedom of Information Act by the National Security Archive. “Legal at State was worried about this yesterday. Genocide finding could commit [U.S. government] to ‘do something.’”

Four years later, President Bill Clinton traveled to Kigali, Rwanda, to apologize to the survivors.

Distributed by MCT Information Services