The fine print of the weekend agreement commits Germany to do what its leaders insist they want to avoid—prop up the weakest countries of the euro zone in future debt crises, even after Europe’s current, €750 billion ($993.21 billion) bailout facility expires in 2013.

WHEN MAKING that open-ended promise to other euro nations, Germany gave up its insistence that investors automatically share in future losses.

Instead, Berlin won a watered-down agreement that will force investors to shoulder losses only if a member state is declared insolvent by a unanimous vote of all euro-zone members.