The Kurdish awakening has emerged from the upheaval of the 2011 Arab Spring, and it is adding fresh disruption to the region's old order. "The events in Iraq, in Syria and in Turkey have profoundly altered the place of the Kurds in the Middle East--they provide fresh impetus and momentum toward Kurdish independence in some form," said Ryan Crocker, who served as U.S. ambassador to Iraq and to Syria and is now dean of the Bush School of Government at Texas A&M University. Such Kurdish independence, he cautioned, "could produce permanent fragmentation of Iraq and Syria--and launch a whole new dimension of instability in the Middle East."

Numbering some 30 million people, the Kurds are one of the world's largest ethnic groups without a state of their own, scattered since antiquity in the mountainous lands straddling today's Turkey, Syria, Iran and Iraq. Their language, Kurdish, is part of the Indo-European family of languages--close to Persian (Farsi) but unrelated to Arabic or Turkish. Unlike Iranians, who are mostly Shiite Muslims, most Kurds are Sunnis.

After World War I, the Kurds sought self-rule at the 1920 peace negotiations between the defeated Ottoman government and the victorious allies. The resulting Treaty of Sèvres called for the establishment within a year of an independent Kurdistan in what is now southeastern Turkey, with the prospect of quick "voluntary adhesion" to the new country by the Kurdish areas of northern Iraq.

But the Sèvres accord was dead on arrival. Mustafa Kemal Atatürk, the founder of modern Turkey, denounced it as treasonous and launched a war that led to the abolition of the Ottoman state. The brief glimmer of hope for Kurdish self-rule was extinguished for generations.

In the following decades, Atatürk's fiercely nationalist Turkey denied the very existence of the Kurds, banning their language and officially referring to them as "mountain Turks." By the mid-1980s, a far-left guerrilla movement, the Kurdistan Workers' Party, or PKK, was fighting a bloody war against the Turkish state (and against fellow Kurds whom it viewed as collaborators). The fighting ended only after the PKK's leader Abdullah Ocalan, who had been jailed by Turkey since 1999, proclaimed a cease fire in March 2013.

Across the border in Iraq, Kurdish autonomy was sometimes recognized, but Kurdish uprisings were ruthlessly suppressed by successive governments. Repression reached its bloody peak in 1988, when Saddam Hussein's forces used chemical weapons against Kurdish civilians during the so-called Anfal campaign. As for Syria, though it backed the PKK against Turkey, it stripped many of its own Kurds of Syrian citizenship. And in Iran, both the shah and the Islamic Republic that overthrew his monarchy in 1979 have suppressed Kurdish aspirations.

The quarreling Kurds, with their alphabet soup of rival political groups, have also repeatedly undermined their own cause. In 1982, Saddam Hussein remarked that he didn't have to worry about the Kurds because they were "hopelessly divided against each other." Indeed, the two main Kurdish factions in Iraq--the Kurdistan Democratic Party and the Patriotic Union of Kurdistan--fought a devastating civil war the following decade, though they had reconciled by the time the U.S. invaded Iraq in 2003, ousting Saddam's regime and giving the Kurds an unprecedented opportunity.