Pity the Syrians as they face the Assad regime's tanks and artillery and snipers. Unlike in Libya, there is no Arab or international "mandate" to protect them. Grant Syria's rulers their due: Their country rides with the Iranian theocracy and provides it access to the Mediterranean. It is a patron of Hamas and Hezbollah. And still they managed to sell the outside world on the legend of their moderation.

True, Damascus was at one time or another at odds with all its neighbors—Turkey, Lebanon, Jordan, Iraq, Israel—but it managed to remain in the good graces of the international community. It had made a mockery of Lebanon's sovereignty, murdered its leaders at will. Yet for all the brutality and audacity of the Syrian reign of terror and plunder in Lebanon, the Syrians were able to convince powers beyond that their writ was still preferable to the chaos that would engulf Lebanon were they to leave.

In the same vein, Damascus was able to pull off an astonishing feat: Syria was at once the "frontline" state that had remained true to the struggle against Israel, and the country that kept the most tranquil border with the Jewish state. (As easily as Syria's rulers kept the peace of that border, they were able to shatter it recently, sending Palestinian refugees to storm the border across the Golan Heights.)

It was the writer Daniel Pipes who rightly said that Syria's leaders perennially wanted the "peace process" but not peace itself. Their modus operandi was thus: Keep the American envoys coming, hold out the promise of accommodation with Israel, tempt successive U.S. administrations with a grand bargain, while your proxies in Lebanon set ablaze the Lebanese-Israeli border and your capital houses Hamas and all the terrible Palestinian rejectionists.

Syria could have it both ways: ideological and rhetorical belligerence combined with unsentimental diplomacy and skullduggery. The Iranians wanted access to Lebanon and its border with Israel. The Syrians sold it to them at a price. They were unapologetic about it before other Arabs, but they kept alive the dream that they could be "peeled off" from Iran, that theirs was a modern, secular nation that looked with a jaundiced eye on the ways of theocracies.

Opponents of the Syrian regime demonstrate outside the Syrian embassy in Ankara, Turkey. The banner in Turkish at center reads: "Telbise, Rastan cry; Let's not become Hama." Associated Press

Syria's rulers were Alawites, schismatics, to the Sunni purists a heresy. Yet as America battled to put a new order in Iraq in place, Syria was the point of transit for Sunni jihadists from other Arab lands keen to make their way there to kill and be killed. The American project there was being bloodied, and this gave the Syrians a reprieve, for they feared they would be next if Washington looked beyond Iraq for other targets.

It was that sordid game that finally convinced George W. Bush that the Syrians had to pay a price for their duplicity. The American support for the 2005 "Cedar Revolution" in Lebanon then followed, and the Syrians made a hasty retreat. In time they would experience a seller's remorse, and they would try to regain what they had given up under duress.

Barack Obama provided the Syrian dictatorship with a diplomatic lifeline. He was keen to "engage" Tehran and Damascus, he was sure that Syrian radicalism had been a response to the heavy hand of the Bush administration. An American ambassador was dispatched to Damascus, and an influential figure in the Democratic Party, Sen. John Kerry, made it his calling to argue that the young Syrian ruler was, at heart, a "reformer" eager to sever his relations with Iran and Hezbollah.

The Arab Spring upended all that. It arrived late in Syria, three months after it had made its way to Tunisia and Egypt, one month after Libya's revolt. A group of young boys in the town of Deraa, near the border with Jordan, had committed the cardinal sin of scribbling antiregime graffiti. A brittle regime with a primitive personality cult and a deadly fault-line between its Alawite rulers and Sunni majority responded with heavy-handed official terror. The floodgates were thrown open, the Syrian people discovered within themselves new reservoirs of courage, and the rulers were hell-bent on frightening the population into their old state of submission.

Until the Arab Spring, nothing had stirred in Syria in nearly three decades. President Hafez al-Assad and his murderous younger brother Rifaat had made an example of Hama in 1982 when they stamped out a popular uprising by leveling much of the city and slaughtering thousands. Now, the circle is closed. President Bashar al-Assad and his younger brother Maher, commander of the Republican Guard, are determined to subdue this new rebellion as their father did in Hama—one murder at a time. In today's world it's harder to turn off the lights and keep tales of repression behind closed doors, but the Assads know no other way. Massacre is a family tradition.

It took time for the diplomacy of the West to catch up with Syria's horrors. In Washington, they were waiting for Godot as the Damascus regime brutalized its children. In his much-trumpeted May 19 speech from the State Department—"Cairo II," it was dubbed—President Obama gave the Syrian ruler a choice. He could lead the transition toward democracy or "get out of the way." Secretary of State Hillary Clinton has since used the same language.

But one senses this newfound bravado is too little too late. With fighting in Afghanistan and Iraq and now Libya, few leaders in the U.S. or Europe want to see the Assad regime for what it truly is. Yet the truth is there for all who wish to see. Ask the Syrians deserting their homes and spilling across the Turkish border about the ways of Bashar and his killer squads and vigilantes with their dirty tricks. They will tell us volumes about the big prison that the regime maintains.

Arab bloggers with a turn of phrase, playing off the expression of "only in Syria," have given voice to the truth about this dreadful regime. Only in Syria, goes one formulation, does your neighbor go to work in the morning and return 11 years later. Only in Syria does a child enter prison before entering school. Only in Syria does a man go to jail for 20 years without being charged and is then asked to write a letter thanking the authorities upon his release. The list goes on. At last, in Damascus, the mask of this regime has fallen, so late in the hour.

Mr. Ajami is a professor at the Johns Hopkins School of Advanced International Studies and a senior fellow at the Hoover Institution. He is co-chair of the Hoover Working Group on Islamism and the International Order.