Andrew Apostolou is a historian based in Washington.

On Sept. 25, Iraq’s Kurdish population will hold an independence referendum. Few doubt that most Kurds will vote yes. It is, however, unclear if the vote will help Kurdistan become independent or create problems that could derail statehood.

The Kurds want independence to end nearly a century of conflict and suffering inside Iraq. Living mostly in Iraq’s north along its Syrian, Turkish and Iranian borders, the Kurds make up between 15 percent and 20 percent of Iraq’s 38 million inhabitants. Unlike most Iraqis, who speak Arabic and follow the Shiite branch of Islam, the Kurds have their own language and are predominantly Sunni Muslims.

The Kurds’ desire to promote their identity through self-government has clashed with Baghdad’s determination to keep Iraq intact. The two sides have also never set a proper boundary between Kurdish and Arab Iraq. In particular, both want to control the city of Kirkuk, which is majority Kurdish and close to major oil fields.

Every attempt at compromise has failed, with violence generally the result. In the 1980s, Saddam Hussein used genocide, killing around 100,000 Kurds and destroying nearly 2,000 villages.

What Iraqi Kurds therefore need is a vote that empowers the Kurdistan Regional Government (KRG), Iraq’s autonomous Kurdish administration, to negotiate independence. A legally valid referendum is a powerful expression of the popular will — when it has a specific mandate. However, the Sept. 25 referendum lacks this legitimacy, making its impact unclear. Nor will the result force any part of the KRG to act — not the president, the cabinet or the parliament.

Part of the difficulty is that there is no KRG constitution. The Kurdish parliament did vote for a constitution in 2009, but it is not in force because it was never approved by a referendum. The 2009 constitution in theory grants Kurdistan the right to hold a vote in line with a referendum law. However, the Kurdish parliament never passed a referendum law. Nor will it. Parliament stopped functioning in October 2015 following conflict between Masoud Barzani, the president of the KRG and the opposition.

That makes the result on Sept. 25 more a declaration of intent than a credible bid for independence. In June, Barzani argued in The Post that “the results of the referendum will bind future Kurdistan governments.” But without a constitution and a referendum law, there is no obligation for future governments to do anything.

As if to prove that the popular vote on Sept. 25 is largely a gesture, the KRG seems to have no plan for the day after. For example, there is no proposal to establish an independent currency if the vote calls for independence. Nor is there an agreed timetable for talks with Baghdad. This is a striking difference from the Scottish independence referendum of September 2014. Scotland had a detailed blueprint to create a separate state in March 2016.

The referendum could also exacerbate the two areas of greatest tension with the rest of Iraq: people and borders. For decades, Iraqi governments expelled Kurds from ethnically mixed areas and replaced them with Arab settlers. Hussein was particularly keen to remove Kurds from Kirkuk, bringing in Arabs from southern Iraq. Every post-Hussein Iraqi government has failed to implement a 2005 deal to compensate these settlers to move to southern Iraq, thereby allowing Kurds to return.

In response, the Kurds will hold the referendum in these disputed regions, which their forces mostly control after they liberated them from the Islamic State. The Kurds will allow Arab settlers and their descendants to vote, including in Kirkuk, even though the KRG wants them out in the long run — a policy of vote now, leave later.

Kurdish leaders are sweetening the pill by arguing they will take disputed territory only by consent and negotiation. Barzani wants “only those territories where the people overwhelmingly want to be part of Kurdistan.” There is, however, no definition of “overwhelmingly.” For example, will 66 percent suffice, a threshold used in Iraq’s 2005 constitutional referendum?

Although Baghdad objects, there is a historical precedent for the KRG’s approach of using votes to determine borders. Germany and Poland divided Upper Silesia in a district-by-district plebiscite in 1921. That voting followed a few years of ethnic conflict and was held under international supervision.

The precedent is, however, an unhappy one. The Germans accepted the loss of territory grudgingly. After Nazi atrocities during World War II, the Poles resolved the issue by expelling the Silesian Germans en masse. The Iraqi Kurds should want to avoid such a violent outcome.

Given Iraq’s failure as a state, the Kurds will become independent eventually. Even Iraq’s prime minister concedes their right to self-determination. What the KRG must understand is that how it leads the Kurds out of Iraq is as important as the goal of an independent state.