This isn't just about replacing one man. It's about challenging his ideas.

The launch of Owen Smith’s campaign for the Labour leadership has left impartial observers rather bemused.

Surely, if the mainstream in the Labour Party wants to defeat Jeremy Corbyn, they should be rallying around a single candidate? Splitting the anti-Jez vote between Smith and Angela Eagle seems utterly self-destructive.

Within a short time, however, it has become apparent that Smith intends to replace Eagle as the candidate.

The argument advanced by his supporters is that he is better placed to beat Corbyn because he is seen as more left-wing by party members. He will therefore ‘peel away’ people who despair of Corbyn’s incompetence, but can’t embrace Angela Eagle’s political world view.

While this may be plausible at one level, we have to be realistic that the chances of either of these candidates beating Corbyn are fairly minimal right now. This is because the Corbynistas are well entrenched and the maths simply doesn’t look that good.  But let’s, for argument’s sake, imagine that Smith could win and Eagle couldn’t.  What would his victory actually represent?

We could see it as the replacement of an incompetent man with someone who seems fairly competent.

But that’s only a fraction of what this trench warfare is actually about.

Corbyn’s personal failings are legion, but it’s his ideology – his ‘pickled dogma’, if I can borrow Neil Kinnock’s famous phrase of the 1980s’ – that we actually need to confront.

I feel that Eagle represents a far greater ideological threat to Corbyn than a man who was clearly reluctant to leave the shadow cabinet in the first place and has spent recent days locked in meetings trying to find a ‘compromise’.

There is no compromise with the climate that led to a brick being thrown through Angela Eagle’s window and threats of violence becoming the norm.

There is no compromise with John McDonnell’s expletive-laden ranting and commitment to extra-parliamentary socialism.

There is no compromise with the return of the very worst of the 1980s.

Things have now gone too far.

Corbyn needs to be faced down by someone who actually wants to reclaim the Labour Party and wave good bye to the destructive forces that have wrecked it in under a year.  Not someone looking naively for hopeless deals.

This is now make or break.