After a week of air assaults on Hamas in the Gaza Strip and Palestinian retaliatory rocketing of Israel's southern cities, the Israeli leadership was at a crossroads. It had to decide whether to embark on a ground offensive or to call it quits and find a face-saving diplomatic endgame (which would leave Hamas with most of its military manpower and firepower intact).
A third alternative was to continue the air campaign while sending in ground forces with limited objectives, designed to curtail Hamas rocketing in specific sectors and to interdict Hamas resupply from Egypt through the tunnels under the Philadelphi axis along the Gaza-Sinai border. A number of Israeli brigades were massed along the Israel-Gaza border, and the troops, according to reports, were raring to go. Last night they went into Gaza.
I believe Israel is right to go ahead: to deliver ground incursions, in various sectors, to bleed Hamas and ultimately to destroy its will and ability to rocket Israel by occupying the border area permanently.
The Israeli cabinet, however, may be more cautious. It has apparently rejected the idea of conquering the strip and crushing Hamas - given the densely packed urban terrain, the limitations imposed by international and internal Israeli opinion and the cost in military and civilian lives.
These considerations are compounded by the fact that the defence minister and Labor party leader, Ehud Barak, and the foreign minister and Kadima party leader, Tzipi Livni, face general elections on February 10 and an electorate unwilling to countenance big sacrifices. At the same time, the leaders cannot allow Hamas to continue rocketing Beersheba, Ashkelon and Ashdod - cities with a total population of some 750,000.
From Israel's viewpoint, the problem is that Hamas, like Hezbollah, will remain - and at some point down the road it can be expected to harass or assault Israel, independently or in collaboration with Hezbollah or Iran. And the basic realities of the contemporary Middle East will remain the same, with Israelis continuing to feel boxed in and under threat.
Israeli foreboding has general sources and specific causes. The general problems are simple. First, the Arab and wider Islamic worlds have never accepted the legitimacy of Israel's creation or the continued existence of the Jewish state, notwithstanding Israel's peace treaties with the Egyptian and Jordanian regimes, signed respectively in 1979 and 1994.
Second, public support for Israel in the West (and in democracies, governments can't be far behind) has steadily withered over the past few decades, as the memory of the Holocaust - which in an ill-defined but general way underwrote Israel - has dimmed and as Arab power and assertiveness have surged. As well, the Israeli occupation of the West Bank and Gaza Strip and its occasionally heavy-handed treatment of the Arabs have played a part.
More specifically, Israel faces a combination of dire short- and medium-term threats. To the east, Iran is advancing its nuclear project, which most Israelis and most of the world's intelligence services believe is designed to produce nuclear weapons. The fact that Iran's president, Mahmoud Ahmadinejad, has repeatedly threatened Israel with destruction quite naturally leaves Israelis deeply perturbed.
In the next year or so, if the world community does not force the Iranians through diplomacy and economic sanctions to halt their nuclear programme, then either the US or Israel will have to attack and destroy the Iranian nuclear facilities.
To the north lies another threat: Hezbollah, a fundamentalist Shi'ite Muslim organisation that vows to destroy Israel and is funded by Iran. It has recovered from the thrashing it received in 2006 when Israeli forces struck into south Lebanon and reportedly now has an arsenal of 30,000-40,000 rockets, some of which can reach Tel Aviv and Dimona, the site of Israel's nuclear facility.
To the south, Hamas will remain Israel's implacable foe, its charter/constitution of 1988 proclaiming the necessity of Israel's destruction "at the hands of Islam".
Between 1948 and 1982 Israel coped relatively well with the conventional threats posed by the armies of the Arab states, trouncing them repeatedly. But the current threats are unconventional and pose a far more difficult challenge. This past week, Israel has taken on one of them, the Hamas rocketry; in future, it is likely to confront - in the absence of cogent western intervention - the far more dire threat of Iran's atomic programme.
Only a change of mindset among the Palestinians, and the wider Arab and Islamic worlds, could allow for peace. And that's not going to happen as long as the Arab world is so strong (and growing stronger) and, at the same time, governed by a mentality of grievance and victimhood.
Benny Morris teaches Middle East history at Ben-Gurion University, Israel, and is author of 1948, A History of the First Arab-Israeli War