The Scots and the Catalans are both ancient European cultures that became part of larger political entities centuries ago but retained distinct identities. Both are today witnessing a strong wave of nationalism and longing for self-rule. There is a major difference, however, in how this is being played out in their respective countries.

The Scottish referendum last month, like the Quebec referendums before it, demonstrated that if people are allowed an open debate and a democratic vote on self-determination, they may well choose to stay in the broader polity. Spain’s hard line on Catalan nationalism demonstrates the opposite: If national ambitions are frustrated, they will only get stronger, more passionate and potentially more dangerous.

The Scottish referendum was watched closely in Spain, but from different perspectives. The Spanish prime minister, Mariano Rajoy, made no secret of his opposition to Scottish independence and suggested he would block an independent Scotland from entering the European Union. Catalan nationalists focused on the process itself as evidence that voting on self-determination is a legitimate right.

On Sept. 11, a week before the Scottish referendum and on the 300th anniversary of the fall of Barcelona in the War of the Spanish Succession, hundreds of thousands of Catalans formed a seven-mile-long “V” for “vote” in Barcelona, the regional capital. And soon after the Scottish vote, on Sept. 18, the Catalan Parliament voted overwhelmingly to formally ask Madrid for a self-determination vote be held Nov. 9. It would ask two questions: “Do you want Catalonia to be a state?” and “if so,” “Do you want Catalonia to be an independent state?”