On June 23, British citizens will cast their ballots in the long-awaited referendum on whether the United Kingdom should remain in the European Union.

Known unofficially as “Brexit,” the referendum represents a watershed moment in Euro

pean politics. It deals with an issue far larger than the political and economic relationship between London and Brussels. What Brexit is fundamentally about is the idea of Europe itself, and whether the notion of an “ever closer” continent — a unquestioned pillar of postwar development — has lasting appeal in 2016, 70 years after World War II.

Poll statistics suggest that it might not. According to the results of a Pew survey released Tuesday — of more than 10,000 participants in 10  major E.U. nations this year — Euroskepticism is on the rise across the continent, even outside of Britain. Only  51 percent of those polled expressed a positive view of the Brussels-based institution, while 42 percent expressed the desire to have certain powers restored to their local governments.

Although E.U. favorability has generally been in decline — with temporary upticks — since 2012, when the Eurozone economic crisis began, it has fallen significantly in the past year. In both France and Spain, for instance, Pew reports that favorability has dropped by double-digits between 2015 and 2016.

As for an explanation, the poll data indicate that “overwhelming majorities” in each of the 10  countries surveyed disapprove of the way the E.U. has handled the migrant crisis, which saw more than 1 million people pour into continental Europe in 2015 alone.

The crisis represents the largest on European soil since  1945, and it is far from over: Just last week, more than 1,000 people died in the Mediterranean while attempting to reach Europe. Brussels has yet to institute a comprehensive rescue policy. Perhaps predictably, the disapproval of E.U. migrant policy is strongest in several of the countries most directly affected: 94 percent of Greeks, 77 percent of Italians  and 88 percent of Swedes polled expressed dissatisfaction.

According to the data, the E.U.’s handling of economic issues “is another huge source of disaffection with the institution.” Approximately 68 percent of Italians, 66 percent of French  and 65 percent of Spanish expressed unfavorable opinions. In Eastern Europe, however, where general support for the E.U. was highest, numbers were different: 47 percent of people polled in both Poland Germany expressed satisfaction. In general, 72 percent of Poles and 61 percent of Hungarians support the E.U.

Returning to the British referendum, a median of 70 percent of those polled in the nine nations outside Britain said a successful “leave” vote would be a bad thing for the European Union as a whole. France was the only country surveyed where more than a quarter of those polled said Brexit would be a good thing: 32 percent expressed that opinion.

But if Brexit was widely looked upon as negative, in six of the ten countries polled, more people expressed a preference for devolution of E.U. power than they did for a stronger Brussels bureaucracy. That is ultimately the issue at stake in Brexit to begin with: whether governance in Europe should be localized or centralized.

Britain may be the only E.U. member state to be staging a referendum, but its citizens are far from alone in their frustrations.