MADRID — A center-left government has fallen. The two-party system has collapsed. The far-right is on the rise. At first glance, Spain seems a lot like other parts of Europe these days. And it is.

But the decision on Friday by Spain’s Socialist prime minister, Pedro Sánchez, to call for an early general election in April — the country’s third since late 2015 — is also an echo of deeper, particularly Spanish dynamics at play.

A secessionist drive in the prosperous northern region of Catalonia has challenged both the country’s territorial integrity and the core arrangements of the 1978 Constitution for Spain, one of Western Europe’s youngest democracies.

The result is the rise of a new nationalism across Spain, which in many ways has yet to fully reconcile the divisions left by the darkest chapters of its recent past, including dictatorship and civil war.