A winning point for any friend of Israel is to compare Israel with any of its neighbours. On any measure - democratic, legal, let alone anything to do with rights - Israel is clearly in a different league from its neighbours.
But a few weeks back I was on a panel with a critical left-wing friend of Israel who made an interesting point. "I'm fed up of hearing Israel compared with Syria and Saudi Arabia' she said. "Israel is a democracy and democracies get held to higher standards." Very true, I thought. Though people do need to realise Israel is rather better behaved than her autocratic neighbours, there is sense in this plea.
As it happens, I've been thinking about it rather a lot. My recent book on Bloody Sunday (the day in 1972 when British troops gunned down and killed 14 British citizens on the streets of a British city) has absorbed me on and off for 10 years. While working on it, I spent plenty of time immersed in what the UK did to fight its war against the Irish Republican Army.
Incidentally, I always find it cringe-making when Brits tell Israelis about Northern Ireland. As sure as the emergence of dietary matters in interfaith meetings, a point about how Israelis might learn from our experience in "the Troubles" is a cliché of British exchanges with Israelis.
This despite the fact that the differences are huge. The IRA, for all its brutality and callousness, never sought the destruction of the British state, or the annihilation of the British people. Its requests were impossible to grant and its tactics bloody, but moderate Republican parties existed throughout the Troubles and the IRA never wanted to drive us into the Channel.
Nevertheless, Northern Ireland always comes up. So, in the spirit of response to my friend's request that we judge Israel by the standards of other democratic states, and conforming to type, allow me one case comparison. I give it not just because so few friends of Israel know about this story, but because so few people outside the small number of us who care about the history of the Troubles know about it.
In the 1980s, British Military Intelligence set up something called the Force Research Unit in Northern Ireland. One of its purposes was to run agents and double-agents within the IRA. One of the agents was known as "Stakeknife". This agent - who was outed in 2003 - was paid and "run" as an agent by the FRU.
With his cover carefully protected, he rose through the ranks, eventually reaching the top of the IRA's internal "nutting squad". That is, he was at the head of the IRA unit tasked with discovering and dealing with - that is torturing and killing - suspected "informants".
This was an extraordinary security coup for British intelligence. To have not merely infiltrated the IRA but to have infiltrated it so completely that, as well as numerous other agents, the Brits got a man to the top of the IRA's internal security unit, demonstrated considerable infiltration success. But it had a striking cost. It meant that in order to protect Stakeknife's cover and advance his reputation and prospects within the IRA , British intelligence allowed a man to torture and kill - and arrange for others to torture and kill - people British intelligence knew to be innocent, including a Belfast pensioner who was killed to protect Stakeknife's cover. Some sources allege that many dozens were killed in this way during the Troubles. But the rationale was that these deaths were needed to keep British agents rising up the IRA's ranks. It was just a shame if you were a poor patsy pensioner.
All this and more happened in what's often called "the dirty war". It certainly was dirty, to an extent still not fully known. But this is what the British state did, rightly or wrongly, to protect its citizens and to subvert, and eventually bring to the table, an organisation with murderous - though not genocidal - intentions. I could go on, could compare Israel's behaviour to the US, France or any developed democracy. But I give this story to make one point: that when we compare Israel not with her despotic neighbours but with other democracies, she comes out rather well.