Any solution to the euro crisis must meet two objectives. One is short run and the other is long run. Unfortunately they tend to conflict.
The first necessary objective is to put Greece, Portugal, and other troubled countries back on a sustainable debt path, defined as a long-term trajectory where the ratio of debt to GDP is declining rather than rising. Austerity won’t restore debt sustainability. It has raised debt/GDP ratios, not lowered them. A write-down would do it. New bigger bail-outs might too, or might not. But either write-downs or bailouts would then create moral hazard and thus make even it even harder to satisfy the second necessary objective.