Nearly every president ends up saying he's sorry for something America has done _ from a bomb gone tragically astray to the locking up of Japanese-Americans during World War II. This time it's disrespectful disposal of Qurans. And again there are critics who see an apology as a sign of weakness or a failure of patriotism.
Should being president mean never having to say you're sorry?
Few would go that far, but there are plenty of advocates for keeping presidential regrets to a minimum.
It seems that the bigger the national blunder, the more controversial the apology.
So saying the U.S. is sorry for the mistaken bombing of the Chinese Embassy in Yugoslavia or the accidental sinking of a Japanese fishing boat is widely accepted. But apologizing for the moral catastrophe of slavery is so contentious that no president has done so.
John Murphy, a University of Illinois associate professor who studies presidential rhetoric, looks at it this way: Nations aren't that different from regular people.
"On a personal level, too, we're much more willing to apologize if everybody involved knows it was an accident," he said. "Oops, I did that, wasn't that stupid of me."
Murphy puts the burning of Qurans at Bagram Air Base in Afghanistan in the category of an accident, although the results have been tragic. At least 20 people, including two U.S. soldiers, have been killed in violence that broke out in protest after Afghans learned that Qurans were among trash dumped into a pit for burning.
The U.S. military's policy is to handle the Muslim holy book with care and respect. In a letter of apology, Obama assured Afghan President Hamid Karzai that "the error was inadvertent" and he would make sure it didn't happen again. A top Pentagon official apologized again Friday at a big mosque in suburban Virginia.
Republican presidential hopeful Newt Gingrich denounced Obama's apology. But he painted it as symptomatic of broader weakness in the Middle East. "This president has gone so far at appeasing radical Islamists that he is failing in his duty as commander in chief," Gingrich said while campaigning in Spokane, Wash.
Another GOP candidate, Mitt Romney, has repeatedly mocked Obama for what he sees as a series of apologies for America's historical misdeeds, "both real and imagined." Romney, who pointedly named his campaign book "No Apology," says Obama's critiques of America's faults are kindling to "anti-American fires burning all across the globe."
But in the speeches in Europe and the Middle East that Romney cites, Obama never said "I'm sorry."
For every critic of national apologies, there are countless people crying out that their suffering, or the mistreatment of their ancestors, hasn't been properly addressed _ advocates of reparations for slavery, for example.
The U.S. House and Senate approved resolutions apologizing for slavery _ more than a century after the Emancipation Proclamation _ but no chief executive has directly done so.
President Bill Clinton sparked controversy when he offered contrition short of a formal apology, telling Ugandan school children in 1998 that "European Americans received the fruits of the slave trade, and we were wrong in that."
Republican lawmakers complained that Clinton had lowered the dignity of his office. Tom DeLay, the House majority whip at the time, said he was offended to see a president "directly or indirectly attacking his own country in a foreign land."
But the next president, George W. Bush, a Republican, spoke to the nation's slave-holding past much more directly, calling it "one of the greatest crimes of history."
In a powerful speech in Senegal in 2003, Bush described the horrors of slavery and the injustices of segregation and said that only through centuries of struggle had America "learned that freedom is not the possession of one race."
But he didn't apologize.
The power of saying "I'm sorry" is supposed to be something everyone learns as a child. So why is it so hard for presidents?
"When a president does this kind of thing it has unusual force," Murphy said. "They are standing up there, representing us as a nation. That's why this gets to be so controversial."
Even a congressional resolution of apology doesn't carry the same emotional weight.
President Ronald Reagan was initially reluctant to apologize to Japanese-Americans who were imprisoned in camps during World War II. He did so after Congress issued its apology and provided for reparations.
Bush apologized for abuse of Iraqi prisoners at Abu Ghraib after the photographic evidence was seen around the world. He called it "a stain on our country's honor and our country's reputation"
After years of pressure by Native Americans, in 2009 Congress passed, and Obama signed, a resolution apologizing "on behalf of the people of the United States to all native peoples for many instances of violence, maltreatment and neglect."
At other times presidents have admitted things have gone wrong, giving the impression of an apology while stopping just short: Bush on his administration's flawed response to Hurricane Katrina, Richard Nixon regretting the Watergate break-in, Reagan on the arms-for-hostages scandal.
Instead of a simple "I'm sorry," Reagan offered: "Mistakes were made."