Not for the first time in his nearly 18 years as Israeli prime minister, Benjamin Netanyahu’s government was wobbling.

Israel’s opposition had called a vote last week to dissolve the parliament and — infuriated by Netanyahu’s repeated failure to pass a law exempting religious students from military service — the two ultraorthodox parties in Netanyahu’s far-right coalition were threatening to back it.

But as coalition officials haggled into the night on the Wednesday in a bid to find a compromise, two men at the heart of the talks knew something far bigger than the coalition’s survival was at stake. Aryeh Deri, head of Shas, the bigger of the two ultraorthodox parties, and Yuli Edelstein, the lawmaker in Netanyahu’s Likud party overseeing the conscription issue, had been briefed that — after decade of threats — Israel was about to carry out a massive attack on Iran and its nuclear programme.