The on-going row over anti-semitism in the Labour party raises the question: how could parts of the party, and Corbyn in particular, have gotten into such a damned mess?

It's not because Labour members have unhappy dealings with the Jews they actually meet. In fact, outside of London and Manchester, the typical Labour member will meet hardly any Jews, and those she meets will almost certainly not inspire any animus.

Instead, the answer lies in the fact that some in the party have for years* adopted the cause of Palestinian rights. There's some justification for this: Labour should be an internationalist party on the side of the underdog. Palestinians, though, are by no means the only people suffering abuses of their human rights. So too are Turks, Kurds, Syrians, Russians, Iranians and so on. The greater interest that some on the left have in Palestine is, I suspect, due to their desire for a moral crusade - for an issue where there is right and wrong**.

Such an urge is dangerous.

For one thing, the cause is futile. There is no good, feasible solution to the Israel-Palestine issue. In this respect, there's a big difference with Apartheid. "End Apartheid now" was a simple and correct slogan in the 70s and 80s. There's no such moral clarity about Palestine. For this reason, Jeremy Corbyn's activism on the issue has achieved pitifully little - much less than, say, Stella Creasy achieved in her campaign on payday lending.

The biggest danger, though, is that treating politics as a moral crusade leads you to blame and stigmatize the other side. Of course, there is logically a massive gap between anti-Zionism and anti-semitism. For at least a few fanatics, however, the gap disappears. As Phil says, there are pockets of anti-semitism in Labour.

I suspect this is a manifestation of a wider tendency within Labour, described by Graeme Archer - Labour's belief in its own moral superiority. Just as some (many?) Labour members think the Tories are evil, so some (a few?) think Jews are for their support of Israel's suppression of Palestinians. The psychological root - an urge for causes in which to demonstrate one's moral superiority - is perhaps the same in both cases.

We don't however, need to see politics as a moral crusade. And given that it leads to sanctimonious divisiveness and even to racism, we shouldn't. Alasdair MacIntyre was right; people have lost the capacity for moral thinking, and (I'd add) it has become little more than an expression of narcissistic self-righteousness.

There are other ways to think of politics.

We could see it as a means of advancing some groups' interests - which is just what Labour was founded to do. Whilst Jeremy Corbyn was laying wreaths and joining pro-Palestinian marches, the capitalist class was assiduously asserting its own interests.

We could also see it as a way of correcting market failures (for example, the under-supply of innovation or climate change) or of solving collective action problems such as the fact that if we all try to reduce debt we'll simply all end up poorer.

Yes, I know this sounds technocratic. And technocracy has its own flaws - not least of which are the tendencies to deceive itself about its ideological nature and to be insufficiently heedful of bounded rationality and knowledge. Given the choice between technocrats and moralizers, however, I'll take the technocrats.

It's long been a cliché that Labour owes more to methodism than to Marxism. This, however, has come at a heavy price - a tendency towards moralizing.

* Though not always. As the late Tony Judt reminded us, socialist Zionism was strong until the late 60s.

** There's a difference here between support for Hamas and support for the IRA. In London in the 80s, it was easy to be sucked into the latter simply because one was surrounded by countless people of Irish extraction wanting you to support political prisoners - and reasonable positions can easily shade into less reasonable ones. Most people, I suspect. faced much less pressure to take sides on Israel-Palestine.