The UNSC (with the shameful exception of the USA) calls for a ceasefire. Both the Israeli Government and the Hamas leaders reject the call. The people of Gaza and of Israel both desperately need a ceasefire. Gaza needs it for obvious immediate physical reasons, and Israel needs it for more long term security reasons, because of the massive stores of anti-Israeli hate that each Palestinian civilian casualty creates.
By rejecting the ceasefire calls, the leaders on both sides demonstrate that they are not acting on behalf of their people, but on behalf of the mutual paranoia scenario that is playing out in their heads. Government has a responsibility to protect their people; therefore neither the Israeli Government not Hamas are governments with true legitimacy.
Another irony: the war proves the illegitimacy of the government, but war also increases the support of people for their government.
As well as demonstrating, we can boycott Israeli goods. (No point in boycotting Hamas goods: they only produce hate-sermons, and who buys them?) There is a page at boycottisraelnow with a list of brands. There is a lot of them, and some are unlikely to be in use by readers of this blog (who wears Armani, or Calvin Klein underpants for god's sake?) but I see Nestle' are there, and surely we can all remember to avoid Nestle, because they push their toxic powder in place of breast milk in developing countries.
PS Raphael has objected to the boycott link above. It does contain ugly, intemperate anti-zionist language. Which is a pity. I use the link to get access to the list of Israel linked companies, and do not endorse any other sentiments on the site. The site does have useful background research. And it has material from Rabbi David Weiss, and anti-zionist.
I will leave the link, with a health warning, until Olmert sits down to negotiate with Hamas, or until the greens here start getting serious about supporting a water project in the Land, whichever comes first...