Seumas Milne Jeremy Corbyn Labour
Seumas Milne has been appointed Jeremy Corbyn's new director of strategy and communication in the UK Labour Party YouTube

Jeremy Corbyn's appointment of Seumas Milne as his party's strategy and communications chief is a stunning circular paradox. That Corbyn would hire a man who, among other things, mourns the Soviet Union's death shows just how desperately he needs strategic guidance.

The hard-left Labour leader has talked up unity in his party because his election risks tearing it apart. Corbyn knows he needs the Parliamentary Labour Party behind him if he is to stand any chance of mounting a forceful, competent opposition to the first majority Conservative government in over two decades.

He needs his MPs to do as he says, not what he has done: such as not rebelling against his leadership as he rebelled time and time again during his 30-plus years as a Labour MP. "On occasions we might agree to disagree," Corbyn said in his debut conference speech, "but whatever the outcome we stand together, united as Labour, to put forward a better way to the misery on offer from the Conservatives."

Well, the hiring of Milne as his Alastair Campbell kills of the myth that Corbyn is interested in party unity because the Guardian's associate editor is one of the most controversial and divisive ideologues on the left of British politics. Milne's unquestioning devotion to hardline socialist politics has led him down some dark intellectual alleys, which are presumably where he met Corbyn.

Among Milne's fruitier moments in his career as a political commentator are defending Stalin against those who would put him at the same level as Hitler when ranking monsters of the 20th century; calling the Baathists and Saddamists who killed British and American troops in Iraq "resistance fighters" who were bravely trying to evict an occupying power; mourning the loss of the Soviet Union because, despite its failures, it was "a powerful counterweight to Western global domination"; and doubting the use of chemical weapons by Syrian despot Bashar al-Assad.

There are countless other eyebrow-raising examples of Milne's ideology, which boils down to a neurotic hatred of the US and a naif idealism about a communism based on democracy and liberty (they are contradictory, and communism by design leads to violent authoritarianism, which George Orwell understood seven decades ago).

As the news broke on Twitter that Milne was being dropped in at the top of Team Corbyn, many moderate Labourites were tweeting in despair. How can they be expected to rally behind the strategy of an ageing commie like Milne, who points to the unfolding economic and political catastrophe in Venezuela – the legacy of Hugo Chavez – as the new model of a socialist alternative to Western liberalism? Where is the unifying strategist who can get Labour MPs of all stripes on side in the fight against a Conservative government?

"We are ashamed in front of the world," wrote Kate Godfrey, a Labour party activist, in a blistering blog post. "The decision to appoint Seumas Milne devalues everything that Labour stands for, and everything that Labour is. It is morally and ethically wrong. Seumas Milne might act for you, Mr Corbyn. He might speak for you. He does not speak for me."

And more than these disagreements, where are Milne's credentials as a political strategist? Or as an expert on mass communication? He is a decent columnist, stylistically speaking, and gives a good speech, but that is it. Perhaps Corbyn was attracted by his educational calibre: the exclusive Winchester College (£35,610 a year in school fees) and then the much-maligned PPE course at Oxford, before embarking on his career in journalism. Oh, and his dad was the director general of the BBC.

Corbyn needs all the help he can get if he is to stand any chance of winning the 2020 general election. He needs someone with genuine experience of strategy, with the scars of battle victory to prove their worth, and of communicating with the ordinary voters he has to win over.

Moreover, the Labour leader needs someone who will challenge and critique him, who can put his assumptions to the test – like the mythical mass of non-voting left-wingers Corbyn believes he can mobilise. Not just another comrade to yell yet more agreement into the self-satisfying far-left echo chamber. And Corbyn needs a person who his rowdy band of MPs can put their faith in, who they can respect even if it is grudgingly.

On none of those counts is that man Milne, a cloistered graduate of privilege whose Guardian screeds are often too unpalatable even for many of its own leftist staff. Milne is a safe choice for Corbyn, with whom he agrees on much. But he is a dangerous choice for Labour Party.