No US president said he was sorry to Vietnam's government.
Being the U.S. president means almost never having to say you're sorry about a war.
Harry Truman didn't apologize for dropping atomic bombs on Japan. No president said he was sorry to Vietnam's government. The same is true for the conflicts in Iraq and Afghanistan.
The issue flared anew after the New York Times reported that Afghan officials said they would require an expression of contrition from President Barack Obama for military mistakes, including causing civilian casualties, in exchange for an agreement over how long U.S. troops could stay in their country.
Secretary of State John Kerry said Afghan President Hamid Karzai hadn't asked for an apology and none would be given. An apology, Kerry said yesterday, "wasn't even on the table."
Because a president's words carry the weight of history, an apology is no simple matter. Such an admission has the potential to undermine the sacrifice of troops and could potentially subject the country to liability for reparations.
"There's a common misperception out there that apologies are somehow simple gestures, and there just couldn't be anything further from the truth," said Jennifer Lind, author of "Sorry States: Apologies in International Politics." She added, "Apologies from one country to another are extremely fraught and, for that reason, historically, are extremely rare."
Differences in law and culture help "explain why apologies are a much bigger deal than you would think," said Lind, a professor of government at Dartmouth College in Hanover, New Hampshire.
The debate is magnified by the power of social media.
Whatever Obama does "there's going to be a whole crew of people unhappy about it," Lind said, noting angry posts on the social-media site Twitter Inc. (TWTR) denouncing the president as "the apologizer in chief."
Karzai has often demanded apologies from the U.S. for civilian deaths, even as more Afghanis have died at the hands of militants than American troops.
"There's a broader sense that getting the Americans to actually admit guilt and literally use the word "˜sorry' does have a certain political value, in Afghanistan and Pakistan and other countries," said Daniel Markey, a senior fellow for South Asia at the Council on Foreign Relations, a policy group in Washington.
A letter from Obama released today didn't apologize or express regret. The closest it came was a comment that the U.S. would "redouble our efforts to ensure that Afghan homes are respected by our forces and that our operations are conducted consistent with your law."
"Saying sorry has no cost if that's all that's required; it's easy," said Graham Dodds, a political science professor at Concordia University in Montreal who has studied official apologies. "But a politician is generally reluctant to do it because it means admitting wrong."
Presidents have apologized for specific atrocities committed by soldiers. Obama expressed "deep regret" over American troops burning Korans, just as President George W. Bush apologized to Iraqi Prime Minister Nouri al-Maliki for a U.S. soldier shooting a Muslim holy book as part of sniper practice.
In 1968, the U.S. admitted in a signed apology to North Korea that the U.S.S. Pueblo had violated territorial waters. In exchange, the captured crew was released.
In 1988, President Ronald Reagan expressed regret over the U.S. downing of an Iranian passenger jet over the Persian Gulf that killed all 290 aboard.
Yet, even years after the fact, presidents don't tend to say they're sorry. In April 1995, President Bill Clinton said "the United States owes no apology to Japan for having dropped atomic bombs on Hiroshima and Nagasaki."
Sometimes presidents leave it to Cabinet officers. On July 4, 2012, Secretary of State Hillary Clinton issued a statement to defuse a feud with Pakistan, saying "we are sorry" about a U.S. military strike that mistakenly killed 24 Pakistani troops. After that, a military supply route was reopened.
Those officials also can be deployed to deliver a non-apology, as Colin Powell did on April 4, 2001, when he refused to tell China the U.S. was sorry for a collision between a U.S. spy plane and a Chinese fighter jet.
"There is nothing to apologize for," Powell said.
Republicans have accused Obama of apologizing too much for U.S. actions. Mitt Romney, the president's challenger in 2012, said the incumbent had gone on an "apology tour" by going to "various nations in the Middle East and criticizing America."
Obama's first trip abroad as president included a speech in Cairo in which he tried to reset relations with the Muslim world. He didn't apologize for the war in Iraq, as Romney suggested. Rather, he called the 2003 U.S. invasion a "war of choice that provoked strong differences in my country and around the world."
Dodds said contrition comes mainly as an official statement from a government or a diplomatic statement intended to gain a result.
The U.S. government and several presidents have apologized for the internment of Japanese-Americans during World War II, he said. On Feb. 19, 1976, President Gerald Ford said the internment was "wrong," a sentiment echoed by Reagan and Clinton.
Other countries are "much less reticent" to issue an apology, Dodds said. "This is sort of a case of American exceptionalism."
And it all comes down to context.
"There's no red line or glass ceiling when it comes to apologies," said Aaron David Miller, a vice president at the Wilson Center, a Washington policy group. "The issue is context."