When Israel expands its offensive against Hamas in the Gaza Strip, many people - watching from a safe distance - are going to be very cross. Human Rights Watch will be up in arms; Amnesty will be outraged. The BBC and CNN will show harrowing pictures (real and fabricated) of Israel's "disproportionate" action. My Facebook feed will be full of friends expressing horror at Israeli airstrikes; #GazaUnderAttack will be trending on Twitter. All this, to the tune of another chorus of "restraint" from foreign diplomatic choirs.
So to everyone who will soon be tutting and sighing in condemnation when Israel strikes back, I say this: speak now, or forever hold your peace.
I say this as someone who wants peace, which I imagine you want too (right?). I say this as a friend, whose stomach churns when he sees pictures of injured children and whose heart breaks when he sees pictures of them dead. I don't want another Cast Lead or Pillar of Defence, so take this as friendly advice, from one who cares desperately about human rights
On the night before Operation Protective Edge was launched, between 8pm and 9pm, Hamas fired one rocket a minute at Israel. Residents of the south have had 15 seconds to run for cover. Hospitals moved premature babies into bomb shelters. Aeroplanes now circle the Mediterranean because of congestion on the Ben-Gurion runway, due to the missile alert.
Israel launched its operation 48 hours after its 48-hour ultimatum to Hamas expired. Don't say you weren't warned. If you fail to condemn Palestinian terrorism, saving your outrage for Israel's response, you will have no moral right to complain.
When you say you care about innocent civilians, nobody in Israel will believe you. When you say you want peace, Israelis will laugh in your face. When you say that violence is not the solution, many will agree with you, but everyone will want to know where you were yesterday, and why you only just remembered you care about crying children it is when Palestinian children who are shedding the tears.
Here's why this matters: if you don't protest now with all your might, you will have zero credibility with the people whose behaviour you wish to influence.
You won't convince Israel to hold its fire when it's clear that you don't care about its people. Why should they listen to you? You will never be able to persuade Israelis to trust your solution if they perceive you as a pathetic rent-a-gob at best or an apologist for global jihad at worst.
So take your "Stop the War"signs and march straight to Trafalgar Square.
Speak now, and speak loudly, because right now, over the wailing of the sirens and shouts of "everyone to the bomb shelters!", it is the echo of your own moral vacuousness and insincerity that reverberates most loudly.