There's a lazy theory among some in our community that - to be blunt - the Conservatives are good for the Jews, and Labour less so. Specifically, that Labour's backbench army of anti-Israel zealots stands in contrast with the more generally pro-Israel stance of the Tories.
The sordid tale of the last government's handling of universal jurisdiction would seem to back that theory. Gordon Brown, it's clear, was personally minded to change the law, as was David Miliband. But they were frustrated by what our political editor, Martin Bright, described a few weeks ago as Jack Straw's masterclass in the black arts of politics - and by the fear that Labour backbenchers would vote against, forcing the government to rely, embarrassingly, on the votes of Conservative MPs.
But that's a misleading case on which to mount an entire theory. In the round, it would be difficult to imagine a more pro-Israel PM than Gordon Brown. Difficult, but not impossible, because his predecessor, Tony Blair, was just that.
Can I share with you my theory about what eventually did for Mr Blair?
The received wisdom is that it was the Iraq war - that, by 2006, his own backbenchers were so sick of him and his war that they wanted shot, and that Gordon Brown's plot to remove him was welcomed with relief.
Some Conservatives refused to attack Israel, but that did not include William Hague
Received wisdom it may be, but it's wrong. Iraq was a running sore, and made his position close to untenable. But only close to untenable. What really did for him was Israel.
By which I mean the Lebanon war. It was Mr Blair's heroic, principled and politically suicidal refusal to condemn Israel's military action in Lebanon as "dis-proportionate" (to use the buzz-word of the day) that finished him off. He was just about the only Labour MP in the Commons who refused to utter a word of criticism of Israel's right to defend itself from Hizbollah.
That was the straw that broke the camel's back. Despite near-universal criticism of his stance, he stood firm - and paid the price as, that summer, Labour MPs decided he had to be removed. Not, I repeat, because of Iraq, but because of Israel.
And that's where the lazy theory to which I referred at the start comes in. Because the condemnation of Israel was near-universal. There were some admirable Conservatives who refused to attack Israel for acting to protect its citizens from terror. But that group did not include the then Shadow Foreign Secretary, William Hague, who indeed led the attack on Israel's "disproportionate" action.
Why do I rake this up again? Because it is fascinating - and worrying - in the context of Mr Hague's debut as Foreign Secretary in Washington last week.
Among his meetings was one at the British Embassy in DC. Mr Hague was asked by a guest about a phrase he used a lot during the election, when he said that the UK would have "solid but not slavish" ties with the US under a Conservative government.
What specifically, he was asked, did this mean? Leave aside the gratuitous insult to Mr Blair, who is surely only regarded in agitprop as the "Bush's poodle" caricature. In what way would Mr Hague have acted differently?
"Israel," the Foreign Secretary immediately replied, before elaborating: "The Lebanon war."
There was, I am told, a pregnant pause as the guests realised the import of what Mr Hague was saying. A Conservative Foreign Secretary was using US (and UK) support for Israel as a stick with which to attack the US-UK special relationship.
So let's have none of this idea that a Conservative government is going, by definition, to be good for Israel. Mr Cameron is an unknown quantity. Mr Hague, the evidence suggests, is all too known. And that is a worry.