Call it a tragic episode, a massacre, even a crime against humanity. But don't—at least officially—call the death and forced displacement of up to 1.5 million Armenians at the end of the Ottoman Empire a genocide. That is what the government of Turkey has long insisted, though seldom more strenuously than in the wake of the most recent attempt in the U.S. Congress to pass a nonbinding resolution that would do just that. Were it to pass, the United States would be on record as seeing the events of 1915-1919 as, in the words of the 1948 U.N. Convention on Genocide, acts "committed with intent to destroy, in whole or in part, a national, ethnic, racial or religious group."
"Why doesn't Turkey do a mea culpa and move on? There just doesn't seem to be a downside to doing that."
(Japan already did it - several times)