There are several lessons, none of them comfortable, for Israel to draw from the weekend's clashes.
The first is that the Arab Spring cannot be dealt with simply by battening down the hatches. The upheavals facing Israel's Arab neighbours mean these regimes no longer have the legitimacy to decide their own Palestinian populations' fates according to narrow self-interest.
The second is that Palestinians have absorbed the meaning of the recent reconciliation between Hamas and Fatah. In establishing a unity government, the two rival factions have belatedly realised that they cannot make headway against Israel as long as they are politically and geographically divided.
The third lesson is that Israel has relied on relative quiet on its borders to enforce the occupations of the West Bank, Jerusalem and Gaza. The peace treaties with Egypt and Jordan, in particular, have allowed the Israeli army to divert its energies into controlling the Palestinians under its rule.
The fourth is that the Palestinian refugees are not likely to remain quiet if their interests are sidelined by Israel or by a Palestinian bid for statehood at the United Nations in September that fails to address their concerns.
And the fifth lesson is that the scenes of Palestinian defiance on Israel's borders will fuel the imaginations of Palestinians everywhere to start thinking the impossible - just as the Tahrir Square protests galvanised Egyptians into believing they could remove their dictator.
