As Secretary of State John Kerry was preparing for peace talks with the Syrian government in Switzerland last week, more gruesome evidence emerged of that regime's brutal nature. A new - and credible - report charged that photographs show the regime has carried out the systematic torture and execution of 11,000 prisoners.
Syrian authorities predictably challenged the authenticity of this sickening revelation.
But it comes from three Britons who have led United Nations war crimes investigations - and three British forensic scientists - in a report funded by Qatar.
And grimly enough, it probably will have little or no practical effect on the peace talks with Syria.
After all, U.S. officials, including Secretary Kerry, have long had no illusions about the murderous, dynastic regime. Last fall, Mr. Kerry accurately called President Assad "a thug" and "a murderer" while deploring the Syrian regime's use of lethal nerve gas to kill hundreds of civilians.
On Wednesday, at the opening day of the conference on resolving the Syrian civil war, Mr. Kerry said, "There is no way, no way possible, that a man who has led a brutal response to his own people can regain legitimacy to govern."
However, President Obama years ago chose a path that minimizes U.S. influence on the civil war in Syria. The latest confirmation of war crimes and crimes against humanity by the Syrian government seems unlikely to change that largely hands-off course.
As Robert Kagan, a strategist at the Brookings Institution, told The New York Times, "The White House has completely hardened itself to whatever horrendous news might come out of Syria because the president doesn't want to get involved."
And that lowers the chances that negotiations will lead to the ouster of President Assad.
The most that can reasonably be hoped for is that the warring sides will allow U.N humanitarian aid to reach the more than 5 million Syrians (a quarter of the nation's population) who are cut off from supplies or have become refugees. And even the chances for that look pretty slim.
That makes the recent flap over Iran's withdrawn invitation to participate in the Syrian talks a largely irrelevant sideshow. U.N. Secretary General Ban Ki-moon rescinded his invitation to Tehran after a strong protest by the U.S. government that Iran did not support the mission of the talks, which is to create a post-Assad regime for Syria.
Iran helps Mr. Assad stay in power by sending him crucial military supplies. The U.S. tries to force him out with words alone.
Meanwhile, the Syrian civil war keeps inflicting human suffering on a vast scale, with atrocities on both sides. Last fall, rebel forces allied with al-Qaida engaged in indiscriminate slaughter of civilians in Latakia province. Human Rights Watch found that the killers were funded by wealthy patrons from Kuwait and elsewhere in the Persian Gulf.
The U.S., which has done little to help the rebels opposed to al-Qaida, has failed to persuade Persian Gulf nations to cut off such backing for terrorist-leaning rebel groups in Syria.
But the most wide-ranging atrocities have been committed by those doing the murderous bidding of Mr. Assad, whose backing comes from Russia as well as Iran.
That doesn't mean the U.S. should intervene militarily in Syria. And unfortunately, we appear to have missed our chance to provide effective material support to rebels who don't have strong ties to al-Qaida.
Thus, President Assad keeps clinging to power, and those peace talks provide scant hope for a positive outcome.
And as the massive carnage continues in Syria, so does Iran's insidious effort to strengthen its influence throughout the Mideast.