By Nikhil Sonnad, qz.com

At the end of this month, one nation will hold a referendum on support for joining the European Union. If it passes, that nation will no longer be known as “Macedonia.”

The referendum will ask Macedonians the following question: “Do you support EU and NATO membership by accepting the agreement between Macedonia and Greece?” The agreement between the two nations would change the name of Macedonia—officially the “Republic of Macedonia,” recognized by international institutions as “The former Yugoslav Republic of Macedonia”—to the “Republic of North Macedonia.”

It’s just one extra word, and as far as words go, you could do a lot worse than “North.” No big deal, right?

Wrong. The prospect of this seemingly minor change has set off major protests in Macedonia, with right-wing constituents opposing any kind of alteration. There have been tear-gas-filled demonstrations in Greece, where many citizens object to the country’s name including the word “Macedonia” at all. The protestors believe Macedonia should be reserved for Greece’s own region of the same name.

It is the latest case of voters around the world, technocrats be damned, putting national identity before perfectly good policies.

On paper, having Macedonia—”North” or otherwise—change its name would be good for all concerned. It would allow the country to join NATO. EU membership, which is currently opposed by Greece, would engender greater democratic institutions in the country and provide it with access to the single market.

Angela Merkel has encouraged Macedonians to vote “yes” to changing the name, saying that the issue is of ”great interest” to Germany and the EU more broadly. And for Greece, the change stands to improve relations with its neighbor. For 27 years, the name has been a source of tension because Greeks believe that the name “Republic of Macedonia” is an attempt to co-opt the heritage of the Greek kingdom of Macedon, which dominated the known world under the leadership of Aristotle’s most impressive student, Alexander the Great.

But as Brexit and countless other recent examples show, international agreements that are “good on paper” are often not enough for voters, who want to protect their sense of national pride. It may be in Taiwan’s best interest, for example, to call itself “Chinese Taipei” at international sporting events. That would shield Taiwan from the wrath of China. But most citizens don’t enjoy capitulating to aggressive whining from a larger neighboring country.

It’s true that the agreement between Greece and Macedonia would in part be a blow to Macedonian identity. In addition to changing its name, the deal insists that Macedonia make no historical or ethnic claims to Alexander the Great or ancient Macedon. Such claims have always been tenuous: The Macedonian language is Slavic rather than Hellenic, closely related to and mutually intelligible with, for example, Bulgarian. The ethnicity of “Macedonian” is also Slavic rather than Greek.

Yet whatever the ethnography, actual Macedonians do identify with some of that history. Only recently did Macedonia remove a statue of Alexander from its main airport terminal. Some Macedonians call themselves (paywall) “Alexander’s descendants.” (Historians think the ancient king did not have children, so this is more of a figurative relationship.) And beyond the issue of Alexander, the modern nation of Macedonia has been around long enough to have developed its own national identity, separate from the Greek interpretation.

The calculus for Macedonia’s name change should be obvious: Just add a “North,” and you get a better-functioning country, more freedom of movement, better access to markets, and a stronger currency. Yet while the referendum is likely to pass, the margin may be slim. The dispute is a timely reminder that identity is as powerful a force as any in determining the way people vote.