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For millions of ethnic Kurds in Iraqi Kurdistan, Monday was a historic day. After a century of despair and neglect, they had the chance to vote for their own independence in a controversial referendum staged by the Kurdistan Regional Government — the body that holds sway over the predominantly Kurdish areas of northern Iraq. Official results are expected in the coming days, with a “yes” vote in favor of independence almost certain to win out.

But for everyone else in the region, this is where the problems begin. U.N. Secretary General António Guterres issued a statement on Monday lamenting the “potentially destabilizing effects” of the vote. The Iraqi government, as well as Turkey and Iran — nations on Iraqi Kurdistan’s borders with sizable Kurdish minorities of their own — have rejected the referendum. Kurdish officials insist the vote is nonbinding, and see it instead as a demonstration of the Kurdish will for self-determination and a pointed message to Baghdad.

But the Iraqi government sent a message of its own, announcing that it was conducting joint military exercises with Turkey near Iraqi Kurdish territory. Iran did the same along its borders and closed its airspace to flights coming in and out of Iraqi Kurdistan.

Proud to cast my vote earlier this morning and partake in this historic day, the day of the #KurdistanReferendum pic.twitter.com/aDP16ZQiud

— Masoud Barzani (@masoud_barzani) September 25, 2017

What was the referendum about?

KRG officials argue that this moment has been long overdue. Since the U.S.-led removal of the Baathist regime of Saddam Hussein in 2003, the Iraqi Kurds have enjoyed a great degree of autonomy from Baghdad and, blessed with considerable oil resources, have been able to build up institutions of a potential future state. Kurdish peshmerga militia have fought on the front lines against the Islamic State, a struggle that has seen close security cooperation between their forces and the United States.

Kurdish politicians, in particular Masoud Barzani, the Kurdish regional president, now sense their moment is nigh amid the upheavals and conflicts roiling Iraq and Syria. And they see a government in Baghdad, led by Prime Minister Haider al-Abadi, that has turned cold toward the Kurds and is barely able to protect its own people.

“Changes happened also about 100 years ago, and the Kurds were bystanders,” Bayan Sami Adbul Rahman, the KRG’s top representative in Washington, told me earlier this year, referring to the Kurds’ historic sense of dispossession as new states emerged out of the ashes of the Ottoman Empire. “We are not going to be bystanders again.”

A ”yes” vote should kick-start a process of negotiations that would pave the way for an eventual separation from Iraq, Abdul Rahman said.

But some critics within the notoriously fractious KRG see the referendum as a bid by Barzani and his ruling party to consolidate power. Two rival prominent Iraqi Kurdish parties, the Patriotic Union of Kurdistan and the Movement for Change, grumbled about the referendum but eventually got on board.

“Both parties see the referendum as a power grab by Barzani, whose grip has been weakened by a prolonged economic downturn triggered by the fall in global oil prices,” wrote Amberin Zaman in Al-Monitor.

Provocatively, the referendum was also staged in the disputed, oil-rich province of Kirkuk, where peshmerga fighters have held sway since 2014, when they rushed into the provincial capital to defend it from the Islamic State. The prospect of violence now seems particularly high there.

A peshmerga soldier celebrates the referendum on Monday outside a voting station in Kirkuk, Iraq. (Chris McGrath/Getty Images)

Why does the outside world oppose the referendum?

Even the United States, which has historically done a great deal to boost the Iraqi Kurds, is dead set against the referendum. U.S. officials fear that a Kurdish independence push now will undermine the campaign against the Islamic State and harm the reelection campaign of Abadi, their favored candidate, in April. Now is not the time, they argue, to rock the boat.

Abadi has deemed the referendum “illegal,” while governments in Turkey and Iran also refuse to recognize the vote’s result. The Turkish government has worked closely with Barzani, but now warned of dire repercussions should the secession movement gain much more steam.

“After this, let’s see through which channels the northern Iraqi regional government will send its oil, or where it will sell it,” Turkish President Recep Tayyip Erdogan said on Monday, warning that Turkey could block the KRG’s oil exports. “We have the tap. The moment we close the tap, then it’s done.”

Turkey, of course, faces its own long-running Kurdish insurgency, which has flared once more in the wake of the Syrian civil war and the rise of a semiautonomous Syrian Kurdish enclave on its southern flank. Ankara, desperate to shove the genie of Kurdish nationalism back into its lamp, dreads the possibility of a functioning, independent Kurdish state breaking away from Iraq.

The Iraqi Kurds do have one conspicuous source of support — the Israelis have long seen the Kurds as useful allies on the Iranian border and have been vocal advocates for their independence in the buildup to the vote.

What happens next?

A yes vote may not prompt an immediate crisis. There’s a hope, suggests David Pollock of the Washington Institute for Near East Policy, that the KRG’s neighbors may moderate their stances after the referendum. “Outsiders will have little choice but to deal with the aftermath in a pragmatic fashion,” Pollock wrote. “As one senior Kurdish official put it privately… this week, ‘We hope that wisdom will prevail.’ “

If it doesn’t, though, and if no productive track of talks emerges between Baghdad and Irbil, then a fuse will have been lit and an already complex geopolitical conflagration will get all the more complicated, especially for the United States.

“Democratic Western states would hardly want to be seen as standing against the collective will of millions of people who had voted for separation from Iraq,” wrote Michael Stephens, research fellow for Middle East Studies at RUSI Qatar, a think tank. “But neither do they wish to be the main architects of a permanent rupture in a fragmented region.”

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