PARTIES never mean to split, but they do it all the same. The principals don’t sit down and work out how they can maximise the damage to themselves and their dreams, yet it still happens.

Even after they’ve told you it isn’t happening - indeed, that it can’t possibly happen - sometimes, somehow, it does. The smartest folk can stumble into disaster.

I don’t know if the misconduct complaints against Alex Salmond will trigger another of those splits that can’t possibly happen until it does, but I wouldn’t discount it. The ingredients are certainly there for a civil war. The peace plan isn’t.

Over the last week, I’ve been struck by the parallels between the events in the SNP and those that doomed the Scottish Socialists.

There are many differences between the two parties, of course, not least scale and electoral success. The hard left was always prone to factionalism, while the SNP has a well-justified reputation for unity. It has a single unifying goal, after all.

But it’s worth looking back to the mid-2000s to remember how the SSP was brought low by the same man who had once raised it high.

Like Mr Salmond and the SNP, Tommy Sheridan was a cornerstone of the SSP. A natural orator and charismatic politician, he dominated his party. He was its first MSP and although the SSP had many unsung hands behind the scenes, without Tommy out front it would never have won six seats at Holyrood in 2003. He was the box office draw.

But Mr Sheridan was also flawed: reckless, egotistical and too fond of combat to let sense prevail.

When a sex scandal struck, he started a legal action that led to disaster. It polarised the SSP. There were those who wanted him to back down - he was accused of visiting a sex club for consensual activity - and those who wanted him to fight it out and sue the News of the World over its reporting. Mr Sheridan resigned as SSP convenor to fight.

Appalled, four of his MSPs and much of the SSP hierarchy turned against him. They felt he was risking the whole party to save his own skin. Two years later, Mr Sheridan and his followers formed their own party, Solidarity. Both it and the SSP live on, but as mere ghosts.

Now, I am not saying Alex is the new Tommy, and the SNP are bound for terminal decline. But the forces unleashed inside the SSP offer a useful cautionary tale. As Mr Salmond’s former SNP deputy Jim Sillars often said, the SNP allowed a ‘cult of personality’ to grow up around his old boss. The same was true of the SSP. But when a party binds its fortune to one giant figure, that figure needs to be perfect. For if they come tumbling down, the party tumbles with them.

Mr Sheridan’s legal case forced people to take sides. If you weren’t with him, you were against him. There was no middle ground. Gender politics were a key part of the split, an issue Mr Sheridan previously had little time for. His female accusers were treated abominably. People put loyalty ahead of facts. Very quickly, SSP members had dug in to positions from where there was no going back.

As with the SNP, people were also genuinely conflicted. Mr Sheridan was not then a pantomime villain. It would be another seven years before he would be jailed for perjury.

He had built an impressive record at Holyrood, driving the end of warrant sales, pioneering free school meals, speaking out on the Iraq War. He was seen as the parliament’s conscience in its early days. He transformed his party’s fortunes.

Like Mr Salmond, party members felt a deep debt of gratitude to him. They did not want to believe the worst. Their instinct was to back him. It was easier to imagine him as the victim of conspiracy or error.

But eventually shock and grief turned to anger and the two camps became irreconcilable. Events took on their own momentum and those loyal to Mr Sheridan broke away.

I don’t know if Ms Sturgeon believes Mr Salmond’s accusers. But she has been relentless this week in backing, in general terms, women who complain about harassment.

She has also stuck by Permanent Secretary Leslie Evans, who led the investigation into the allegations, and who Mr Salmond has repeatedly attacked. Ms Evans was “absolutely right to ensure that the procedure was applied in this case and she has my full support in having done so,” Ms Sturgeon said.

If the First Minister does believe the women, imagine how Mr Salmond’s actions would strike her.

From that perspective, she would not see a Nationalist hero defending himself against injustice, she would see a sexual menace prepared to risk incalculable damage to his own party and its cause in order to maintain his own mythology.

From that perspective, she would see someone willing to burn everything to the ground, so long as he got out unscathed. That is the perspective from which many in the SSP came to view Mr Sheridan, and for them it was unforgivable. It caused a rift that could never heal.

Some SNP MSPs are already wondering about the depth of Mr Salmond’s concern for the party. “His attitude seems to be, ‘I built it so I can break it’,” one told me.

The crisis is hugely unpredictable. The divisions in the SNP could stop spreading. The opposition attacks could backfire and unite the party. Ms Sturgeon and Mr Salmond could laugh off their differences and light up the SNP conference like the double-act of old. The complainers could decide they were mistaken about one of the biggest decisions of their lives, and Ms Evans could admit she botched the whole thing up.

The only thing we know for sure is that the SNP won’t split, because that is obviously impossible.