European Union leaders say they have a new deal on migration. It’s hardly that: They came up with a text but no clear agreement on what to do. The plan is a muddle that leaves important details blank. Most important, it ducks the main challenge: to devise a common E.U. policy on refugees.

The E.U. has been struggling to deal with an inflow of migrants from across the Mediterranean Sea. Southern European countries, especially Italy and Malta, have spent heavily on rescuing people at sea and processing refugees. The job falls to them because of a controversial rule — the so-called Dublin regulation — which says that asylum applications should generally be handled by the country of entry.

The number of new arrivals has fallen sharply since the peak in October 2015, but dealing with the consequences of earlier migration is still difficult. Resentment of migrants and of the E.U.’s part in the problem is, if anything, still growing. It was decisive in propelling the League, a right-wing xenophobic party, to its place in Italy’s government. In Germany, Chancellor Angela Merkel has come under pressure from the Christian Social Union, a junior coalition partner, to restrict the movements of migrants within the E.U.

The new agreement takes several small steps. Leaders said they would set up “controlled centers” across the E.U. to process migrants, but only on a voluntary basis — suggesting that Italy should expect little relief. The plan also talks of exploring whether centers could be set up outside the E.U., most likely in north and west Africa — but again that calls for volunteers. Crucially, Europe did nothing to revise the Dublin agreement; in fact, the leaders agreed that any changes to that accord would require consensus, giving a veto to hard-line governments such as Hungary’s.

One of the E.U.’s proudest achievements is its single labor market, allowing workers to move freely among member countries without internal barriers. The implication is obvious: Europe needs a single policy on refugees. The E.U. should commit more money to securing the external border and have one centralized system to allocate refugees fairly across countries.

FROM AN EDITORIAL ON BLOOMBERG VIEW