‘Brexit’ Pain for Europe Gives Cameron Leverage in Crucial Week

The argument that the 28-nation bloc would be weaker without its second-biggest economy gives Cameron leverage as he closes in on a deal to reset the U.K’s terms of membership ahead of a stay-or-leave referendum. Bones of contention remain the extent to which financial regulations in the euro region would affect the City of London. High noon is a Feb. 18-19 summit of leaders in Brussels.

Losing Britain would crimp Europe’s economy and risk further roiling the region’s financial markets after the shares of the continent’s banks had their worst start to the year since at least 1987. It would also threaten the EU’s clout by undermining the standing of the world’s richest club in international forums, while adding succor to populists at home agitating to follow the U.K. out the door.