But Mr. Sánchez’s economic model, which is inextricable from his approach to migration, is overrated and in many ways harmful. Spain’s economy has for years been heavily based on tourism, relying on an influx of unskilled workers to staff its hotels and restaurants. This generates cash, but has done little to advance Spain into the ranks of Europe’s more advanced economies. Mr. Sánchez did not invent this model, but he has made it his own. That has not won him as much gratitude in Spain as elite opinion would lead you to believe.