It is not just Israel that can claim a right of self-defence. Palestinians have exactly the same right, although far less ability to achieve it.
Defence means protecting one’s people and property against an aggressor and, in recent days, as in the rest of the conflict between Israel and Palestine, Israel is very much the aggressor.
The Israeli military is ranked 11th for power in the world. It has tanks, artillery, rocket-launchers, aircraft, helicopters and a navy. It receives more than $3 billion (£1.7bn) each year in American military aid plus more than $700m this year and next for the missile defence shield.
Against this, Hamas is firing home-made rockets and for technology has mobile phones and pick-up trucks.
Israel has sophisticated electronic surveillance systems, its own Ofek series of military satellites and co-operation from America in its intelligence and military operations.
We saw in the Iraq war that bombs could be dropped with precision down chimneys, yet we read that Israel has been hitting schools, hospitals and civilian targets in its attacks on Gaza. The only possible conclusion is that these actions are deliberate.
As a result, of the 661 deaths (up to Monday) 632 are Palestinian, 29 Israeli; that is more than 95 per cent Palestinian deaths. Since the year 2000 around 85 per cent of all casualties, including children, have been Palestinian. Taking all this together it is clear that Israel has used grossly disproportionate force against the Palestinian people – that is a war crime in international law.