If you are wondering why Hamas launched its all-out assault on Israel on Saturday, I wrote it here last week. “The Arab world has basically abandoned the Palestinians to their fate, whatever that may be. Six Arab countries have established diplomatic ties with Israel and several more, including Saudi Arabia, are on the brink of doing so.”

Hamas’s leaders desperately want to recover the de facto veto that Palestinians once had on the concessions other Arabs make to Israel, and this is the only way they might get it.

The “mighty vengeance” Israel’s Prime Minister Binyamin Netanyahu promises to rain down on the Gaza Strip is exactly what Hamas actually wants. The whole point is to get the Israelis to send its soldiers in on the ground, because that’s when the casualties start going up steeply.

Hamas doesn’t care if 10 Palestinians die for every Israeli in the forthcoming “operation” (which is what will happen, because Israel’s weapons are vastly superior and the fighting will be in densely populated civilian areas). The dead Palestinians will all be “martyrs”, and their deaths will freeze Israel’s peace initiatives with other Arab countries.

The commanders of the Israeli Defence Forces (IDF) understand all this, but the political leaders whom they must obey desperately need to wreak a “mighty vengeance” on Gaza. At least 600 Israeli civilians have been killed in their cars, at a music festival or in their homes, and the Israeli public expects and will accept nothing less than the traditional 10-to-one kill ratio. (It’s taboo to say that publicly, but everybody knows it’s true.)

So the IDF will go into the Gaza Strip in force despite the Israeli hostages there, who will be murdered on video in a variety of ugly ways. Four or five thousand Palestinians will die, together with some hundreds of Israeli soldiers, and Israeli peace talks with other Arab countries (but never with the Palestinians) will stop for a while. That’s the “happy” ending.

A much unhappier but still obscure ending starts with the Palestinians on the occupied West Bank joining the fight. They are more numerous than the Palestinians in Gaza (3 million), and there has already been a low-level insurgency under way in the West Bank for several years. (Deaths in the low hundreds, usual ratio.)

If large numbers of young Palestinians in the West Bank join the militants, the IDF will be badly stretched to control both areas at the same time. And that might tempt Hezbollah to join in.

Hezbollah is a powerful Lebanese militia that controls the southern border region with Israel. They are not Palestinians, but as Shia Muslims they get lavish weapons supplies from Iran. They have an estimated 130,000 rockets of every kind, and the last time they faced the Israelis, in 2006, they fought the IDF to a stand-still.

Hezbollah’s leaders have their own issues and don’t want to join this war, but things can easily get out of hand in this region. (There was a brief exchange of artillery fire between the IDF and Hezbollah on Sunday.) If Hezbollah should be drawn into the war too, we might all be in trouble.

It’s still true that Israel cannot lose this war: the local military balance is overwhelmingly in its favour. But it could get hurt badly enough to panic if things go sideways for a while, and the people in charge politically in Jerusalem will be looking for a decisive victory to rinse away their recent sins of omission. That makes them dangerous.

There are also extremists in Netanhyahu’s cabinet who would welcome a small war in the West Bank to let them do some ethnic cleansing, which in this situation is ultra-dangerous. Everybody needs to proceed with the utmost caution in coming days, but we know some won’t.