"I will play music and celebrate what the Israeli air force is doing." Those chilling words were spoken on al-Jazeera on Saturday by Ofer Shmerling, an Israeli civil defence official in the Sderot area adjacent to the Gaza Strip. For days Israeli planes have bombed Gaza. Almost 300 Palestinians have been killed and a thousand injured, the majority civilians, including women and children. Israel claims most of the dead were Hamas "terrorists". In fact, the targets were police stations in dense residential areas, and the dead included many police officers and other civilians. Under international law, police officers are civilians, and targeting them is no less a war crime than aiming at other civilians.

Palestinians are at a loss to describe this new catastrophe. Is it our 9/11, or is it a taste of the "bigger shoah" Matan Vilnai, the deputy defence minister, threatened in February, after the last round of mass killings?

Israel says it is acting in "retaliation" for rockets fired with increasing intensity ever since a six-month truce expired on 19 December. But the bombs dropped on Gaza are only a variation in Israel's method of killing Palestinians. In recent months they died mostly silent deaths, the elderly and sick especially, deprived of food, cancer treatments and other medicines by an Israeli blockade that targeted 1.5 million people - mostly refugees and children - caged into the Gaza Strip. The orders of Ehud Barak, the Israeli defence minister, to hold back medicine were just as lethal and illegal as those to send in the warplanes.

Ehud Olmert, Israel's prime minister, pleaded that Israel wanted "quiet" - a continuation of the truce - while Hamas chose "terror", forcing him to act. But what is Israel's idea of a truce? It is very simple: Palestinians have the right to remain silent while Israel starves them, kills them and continues to violently colonise their land.

As John Ging, the head of operations for the United Nations Relief and Works Agency for Palestine Refugees, said in November: "The people of Gaza did not benefit; they did not have any restoration of a dignified existence ... at the UN, our supplies were also restricted during the period of the ceasefire, to the point where we were left in a very vulnerable and precarious position and with a few days of closure we ran out of food."

That is an Israeli truce. Any act of resistance including the peaceful protests against the apartheid wall in the West Bank is always met by Israeli bullets and bombs. There are no rockets launched at Israel from the West Bank, and yet Israel's extrajudicial killings, land theft, settler pogroms and kidnappings never stopped for a day during the truce. The western-backed Palestinian Authority of Mahmoud Abbas has acceded to all Israel's demands. Under the proud eye of United States military advisors, Abbas has assembled "security forces" to fight the resistance on Israel's behalf. None of that has spared a single Palestinian in the West Bank from Israel's relentless colonisation.

The Israeli media report that the attack on Gaza was long planned. If so, the timing in the final days of the Bush administration may indicate an Israeli effort to take advantage of a moment when there might be even less criticism than usual.

Israel is no doubt emboldened by the complicity of the European Union, which this month voted again to upgrade its ties with Israel despite condemnation from its own officials and those of the UN for the "collective punishment" being visited on Gaza. Tacit Arab regime support, and the fact that predicted uprisings in the Arab street never materialised, were also factors.

But there is a qualitative shift with the latest horror: as much as Arab anger has been directed at Israel, it has also focused intensely on Arab regimes - especially Egypt's - seen as colluding with the Israeli attack. Contempt for these regimes and their leaders is being expressed more openly than ever. Yet these are the illegitimate regimes western politicians continue to insist are their "moderate" allies.

Diplomatic fronts, such as the US-dominated Quartet, continue to treat occupier and occupied, coloniser and colonised, first-world high-tech army and near-starving refugee population, as if they are on the same footing. Hope is fading that the incoming administration of Barack Obama is going to make any fundamental change to US policies that are hopelessly biased towards Israel.

In Europe and the Middle East, the gap between leaders and led could not be greater when it comes to Israel. Official complicity and support for Israel contrast with popular outrage at war crimes carried out against occupied people and refugees with impunity.

With governments and international institutions failing to do their jobs, the Palestinian Boycott, Divestment and Sanctions National Committee - representing hundreds of organisations - has renewed its call on international civil society to intensify its support for the sanctions campaign modelled on the successful anti-apartheid movement.

Now is the time to channel our raw emotions into a long-term effort to make sure we do not wake up to "another Gaza" ever again.

• Ali Abunimah is co-founder of The Electronic Intifada and author of One Country: A Bold Proposal to End the Israeli-Palestinian Impasse

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