In April of 1937, the war planes of Nazi Germany and fascist Italy chose a market day to bomb a Basque town, one of the first times a civilian population was deliberately targeted. Pablo Picasso, a native of Spain, quickly reacted by depicting the horror in his famous mural named for the town, “Guernica.” It was finished by June. If he were alive today, he might want to paint one called “Aleppo.” It should be mounted outside the White House.

Aleppo is not some quaint market town. It is — or was — Syria’s major city, an ancient trading center, a cosmopolitan stop for many a camel caravan. It is now being leveled by incessant bombings, the occasional use of chemical weapons, barrel bombs and, recently, bunker busters that entomb the wounded. Even ambulances and rescue workers have been targeted. Aleppo, like Guernica before it, is where the world is learning a lesson it seems always to forget.

Barack Obama tells every interviewer he’s anguished over Syria, but that is scant compensation to the victims and it has not moved the Russians or the Syrian government to halt their bombing. Secretary of State John Kerry, like some hapless suitor offering wilted flowers, has been appealing to Vladimir Putin’s wholly imaginary better angels. Putin takes the flowers and then bombs some more. Unlike Obama, he knows what he wants. He wants to win.

This is not Kerry’s failure. It is Obama’s. He takes overweening pride in being the anti-George W. Bush. Obama is the president who did not get us into any nonessential wars of the Iraq variety. The consequences for Syria have been dire — perhaps 500,000 dead, 7 million internal refugees, with millions more coming at Europe like a tsunami of the desperate.

European politics has been upended — Germany’s Angela Merkel is in trouble, Britain has bolted the European Union, and Hungary and Poland are embracing their shameful pasts — but there is yet another casualty of this war, the once-universal perception that America would never abide the slaughter of innocents on this scale. Yet, we have. Obama has proclaimed doing nothing as doing something — lives saved, a quagmire avoided. But doing nothing is not nothing. It is a policy of its own, in this case allowing the creation of a true axis of evil: a gleeful, high-kicking chorus line of Russia, Iran and Bashar Assad’s Syria. They stomp on everything in their path.

Aleppo then is like Guernica, a place of carnage. It’s also a symbol of American weakness. The same Putin who mucks around in Syria has filched American emails and barged into the American election. He has kept Crimea and a hunk of Ukraine and may decide tomorrow that the Baltics, once Soviet, need liberating from liberation. He long ago sized up Obama: all brain, no muscle.

All over the world, American power is dismissed. The Philippine president, a volcanic vulgarian, called the president a “son of a whore” and, instead of doing an update of sending in the fleet, Obama canceled a meeting. China constructs synthetic islands in the Pacific Ocean, claiming shipping lanes that no one should own, and every once in a while an American warship cruises close — but not too close. We pretend to have made a point. The Chinese wave and continue building. The North Koreans are developing a nuclear missile to reach Rodeo Drive, and God only knows what the Iranians are up to deep in their tunnels.

Does all this stem from Uncle Sam’s bended knee in Syria? Who knows? But America’s reluctance to act has almost certainly given others resolve. There was never any need for the U.S. to put boots on the ground — that has been Obama’s straw man, a totally fatuous excuse for inaction. A no-fly zone over Syria, just like the one George H.W. Bush imposed on Iraq to stop Saddam Hussein’s slaughter of the Kurds, would have saved countless lives. An Assad without an air force and his killer copters might now be Dr. Assad, the London eye doctor he once was. The Russians would have likely stayed out of Syria and the Iranians and their chums, Hezbollah, would still be minding their own business instead of propping up this revolting regime.

The mural of Guernica once seen is not forgotten — the anguished faces, the twisted bodies, the hideous deformities of violent death. Now we have the photo of the Syrian boy in an ambulance, iridescent red, powdered with the dust of gone buildings, staring vacantly at a world where, for him, there are no adults. Once again, little is being done. Once again, worse will follow.

Richard Cohen is a columnist with The Washington Post. His email address is: cohenr@washpost.com.