ROME — Another European election, another scene of political carnage. The stunning showing by the Five Star Movement and other populist parties in Italy’s election on Sunday shattered the establishment and suggested that the country was at the cusp of a political revolution.

Except Italy is Italy. A complicated law passed last year — and aimed at Five Star — made it difficult for any single party to win the election. Now, in typical Italian fashion, there is a muddle: No party, or coalition, has won enough support in parliament to form a government, thrusting the country into protracted negotiations over who will govern.

Which is to say, things were going according to plan.

On a continent that has been torn apart more than once by cataclysmic wars, many countries have built in safeguards against political extremes. But the question for Italy — and all of Europe — is how much longer these protections will hold.

Germany has a highly decentralized, consensus-based system. France has a two-step election that allows its citizens first to vote their hearts, and then their heads.