The writer is the president of the Council on Foreign Relations. He was the US envoy to the Northern Ireland peace process from 2001-03.

Israeli missiles continued to fall on Gaza; meanwhile, a bus was blown up in Tel Aviv. But by the end of Wednesday, a ceasefire agreement between Israel and Hamas, and brokered by Egypt and the US, was signed. However, there is a big difference between a truce that is an interlude between rounds of fighting and one that presages a promising political process. It might take a willingness to learn from Northern Ireland, of all places, to tip the scales towards the latter.

Decades of violence – "the troubles" – set the backdrop to negotiations. Success had it roots in British policy. London’s objective was to end the terrorism and bring about a political settlement. Doing so required persuading the Provisional IRA that it would never be able to shoot or bomb its way into power and that there was a political path open to it that would satisfy some of its goals and many of its supporters, if it would act responsibly.

The government of Israel has internalised the first but not the second part of Britain’s strategy. Israel has carried out massive air strikes that have reportedly destroyed the bulk of Hamas’s Iran-supplied, longer-range missiles and killed dozens of Palestinians, including Hamas’s military chief.

But military force has limits...