Bangladesh, Sept. 25 -- European Union ministers recently reaffirmed that enlargement remains a “top priority” despite the blocs growing challenges. The rhetoric of expansion is nothing new, of course. What is new is the degree to which this mantra now collides with harsh realities: economic decline, a fractured energy landscape, and the worlds geopolitical reorientation. The paradox of seeking enlargement while facing internal disarray may well define the Unions next decade.

A recent Bruegel report lays bare the structural dilemmas. The study points to rising fragmentation in global trade, higher energy prices, and weakened competitiveness. It warns that Europe risks falling further behind in innovation and productivity, esp...