A row is brewing in the Commons over Labour's stance on the Immigration Bill, which has its second reading this evening. The party's whips told MPs this morning that they would be on a one-line whip for this piece of legislation, with the plan being to abstain on the vote itself. Centrist MPs in particular are angry about this, suggesting the Labour leadership is trying to 'pander to Ukip' by not opposing the Bill outright.

Abstaining at Second Reading is normally something a party does to signal that it supports some aspects of a bill, while having concerns about others. It neither wants to oppose or support the legislation outright at this stage. In this instance, the Immigration Bill ends free movement, and brings EU citizens living in the UK under domestic immigration law. Labour is keen not to appear to oppose the results of the EU referendum, including the end of freedom of movement, but it is anxious about the implications for EU citizens' rights. The party can push for changes to this aspect of the legislation in the ensuing stages, though, hence today's abstention.

This is still an interesting move from Labour's frontbench, though. The Jeremy Corbyn approach was once to paint in primary colours, opposing bills with anything remotely unpalatable in them as soon as the opportunity arose. Indeed, one of the things that ignited Corbyn's first leadership campaign in 2015 was the decision of the party's interim leader Harriet Harman to abstain on the second reading of the Welfare Reform Bill. Her rationale was that Labour had just emerged from a general election campaign in which voters told it repeatedly that it wasn't good with money and couldn't be trusted on welfare, so the party could not appear to oppose reform. The party couldn't support certain measures, so it would seek changes in the ensuring stages of the Bill's passage through Parliament.

It seemed obvious to Harman - and those working on the leadership campaigns that were, at this stage, considered the 'mainstream' ones - that Labour activists would agree, given they'd been standing on the same doorsteps for the past few months hearing exactly the same thing from voters. But the great shock of the contest was that the party membership was not thinking what Labour MPs were generally thinking - hence Corbyn's rise to power.

The Left of the party hated the idea of abstaining, and argued against it for all the reasons the 'moderates' are deploying today: it's not a strong message and it suggests Labour is ambivalent to the moral outrages they see in the legislation as it stands. In other words, there's too much nuance.

That's the thing about being in charge, rather than being the downtrodden minority group in a party: you end up realising that nuance is actually quite important if you want to win power. Corbyn and his comrades are just the latest political group to catch on to that.