I suppose that if you are under thirty, Northern Ireland seems a place far away and it must be difficult to imagine a time when news from the province was a regular feature of the BBC and ITV nightly news bulletins. The Good Friday Agreement, for all its imperfections and awkward compromises, settled something that now belongs to something close to ancient history. A YouGov poll last month suggested only one in five voters thought they knew even a fair amount about Jeremy Corbyn’s history with Sinn Fein, the IRA, and the wider republican movement.

The young can be forgiven their ignorance. But there are many people old enough to remember what really happened in the 1970s, 1980s and 1990s who seem determined to ignore historical record. In some curious, inchoate, fashion dredging these things up is considered poor form, tiresome carping on about dusty history and even, sometimes, an example of how a good and kindly man has been traduced by appalling people armed with nothing more than the historical record of what he did, what he said and what he thought.

Insisting upon the historical truth, demanding that we remember and acknowledge that what happened really happened, is now a 'smear' designed to influence the outcome of this election. Because, look guys, it was all a long time ago, so surely we can let bygones be bygones and move on. If the Queen can meet Martin McGuinness, why can’t everyone else let the past go?

It’s a reasonable question, even if it is also one that asks us to indulge a false account of Irish and British political history. The truth of the matter is well-established: by the time Jeremy Corbyn entered parliament, only people actively sympathetic to the provisional IRA hung out with Sinn Fein politicians or attended Troops Out efforts.

In Britain, only the far-left considered the SDLP - Labour’s parliamentary allies, remember - lickspittle sell-outs little better than the Unionists they ostensibly opposed. Only the far-left welcomed the Brighton bombing that almost succeeded in assassinating the British Prime Minister and her cabinet. Only fringe leftist publications such as Labour Briefing, whose mailing list Jeremy Corbyn reportedly organised and at whose events he spoke at, claimed that only 'an unconditional British withdrawal, including the disarming of the RUC and UDR will allow for peace in Ireland'.

In December 1984 - after the Brighton bombing - the magazine 'reaffirmed its support for, and solidarity with, the Irish republican movement'. Not, note, the nationalist movement but the republican movement. The nationalists in the SDLP were too peaceful, too dedicated to constitutional politics, too decent to be thrilling or attract the support of far-left Brits imagining themselves daring revolutionaries. The British, Labour Briefing enthused, 'only sit up and take notice when they are bombed into it'. Labour Briefing was made of stern stuff:

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'We refuse to parrot the ritual condemnation of ‘violence’ because we insist on placing responsibility where it lies… Let our ‘Iron Lady’ know this: those who live by the sword shall die by it. If she wants violence, then violence she will certainly get'.

Now we are asked to disregard all of this and accept the view that Jeremy Corbyn’s record of accommodating and forgiving republican terrorism should not be held against him now. He should receive some kind of mulligan.

As the Guardian, that noted bastion of Orangeism, said in an editorial in 1996: 'Mr Corbyn’s actions do not advance the cause of peace in Northern Ireland and are not seriously intended to do so'. That was a week after an IRA bomb had exploded in London’s Docklands, in response to which Corbyn invited Gerry Adams to Westminster. As the Guardian put it, this episode provided a showcase for Corbyn’s 'abiding' qualities:

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'...his lack of wider political and moral judgment, his predilection for gesture politics, his insensitivity to the feelings of most Londoners and his indifference to the policies of his party'.

The paper concluded, 'Mr Corbyn is a fool, and a fool whom the Labour party would probably be better off without'. Just another 'smear', I suppose.

It is true that the UK government talked with terrorists. True that it opened unofficial, back channel, communications with the Provisional IRA at regular intervals. True that, since the peace process reached its tipping point, Sinn Fein have become almost respectable and, as such, have been welcomed into the body of the kirk, the better to ensure there is no slippage and no return to the ghastly bad old days. But those government contacts were of a quite different order to Jeremy Corbyn’s contacts and relationship with the republican movement. They were contacts designed to explore the possibility of ending the violence. They were not conducted in a spirit of fellow-travelling. For Corbyn and his ilk, only the provisionals represented the true spirit of Ireland. They, not constitutional nationalists, were the legitimate voice of Ireland. It was a shameful position to hold then and no amount of whitewash or revisionism can alter that.

Not all the blame for the failure to end the violence sooner can be pinned on the Provisional IRA and Sinn Fein, but a lot of it can be. Noting this does not require us to condone everything done by the British authorities or to turn a blind eye to Loyalist terrorism. Far less does it require us to accept or whitewash the stupidity and cruelty of the Unionist Stormont government whose bigotry and denial of basic civil rights to the Catholic, nationalist, minority played a large part in sparking the conflict in the first place.

Nonetheless, by the time Corbyn became an MP the outlines of a settlement were already known. There was never any great mystery about how this could be achieved. Not for nothing did Seamus Mallon call the Good Friday Agreement 'Sunningdale for slow learners'. It is a grim tragedy that it took 20 years of carnage for the warring factions to tire of the violence and recognise that peace, even if it meant accepting the previously unacceptable, was acceptable.

By that stage, primary responsibility for the continuing violence lay with the provisional IRA. If the IRA agreed to put the guns away, peace might be possible. But throughout the 1980s and early 1990s it was the IRA’s refusal to countenance a ceasefire that, more than anything else, prolonged the conflict. By then it was clear the IRA could not bomb Britain out of Northern Ireland but the violence continued. A ceasefire was a necessary precondition for peace talks but, as far as I am aware, there is no record of Jeremy Corbyn pressing his republican allies for a ceasefire.

The momentum for peace would not come from the far-left, but from the constitutional nationalists they despised. The Hume-Adams talks - facilitated by Charlie Haughey, the Irish Taoiseach - began in January 1988 and lasted five years. The Provos had begun their long march in from the cold but progress was sporadic and subject to countless setbacks, not the least of which was the ongoing IRA campaign. The Irish government and the SDLP each accepted that peace would be impossible without a credible and lasting IRA ceasefire. If much of the preparatory groundwork for this was laid by nationalists, the British government had a role to play too. When Peter Brooke, Secretary of State for Northern Ireland, declared in 1989 that Britain had 'no selfish strategic or economic interests in Northern Ireland' he signalled that, even though Margaret Thatcher was still Prime Minister, an opening was possible.

I mention all this in some small detail because it puts the lie to the notion that Corbyn was a tireless campaigner for peace. No contemporary evidence supporting this proposition has been furnished by his office, doubtless for good reasons. It seems worth noting that Corbyn does not feature even once in definitive histories of the period such as Ed Moloney’s 'The Secret History of the IRA'. Nor do those who were there, people such as Seamus Mallon, recall Corbyn’s useful contributions to the peace process. Truly, he must have been the most secret peacemaker of all.

Instead he exemplified a mindset that viewed Northern Ireland as a colonial problem. Hewing to standard republican orthodoxy, the far-left took the view that because Northern Ireland was an artificial creation its future could, and should, be decided in the imperial capital. And because it should not have existed in the first place, the path to peace assumed that it should not exist in the future either. A mindset and an attitude, in other words, that made peace impossible.

It did so because, far from favouring self-determination (except on an impossible all-island basis) it opposed Northern Irish self-determination, precisely because the people of Northern Ireland would have given - as they continue to give - the wrong answer to that question. This was, to be fair, republican orthodoxy too but peace was impossible until the principle of consent was agreed. John Hume always knew this; by the late 1980s and early 1990s Gerry Adams knew it too. Peace would be based, as had been proposed at Sunningdale, on a power-sharing assembly in Belfast. Northern Ireland would be transformed, but it would remain British until such time as its people determined otherwise. In response for intellectual capitulation, Sinn Fein would be rewarded with a hefty share of the peace spoils. A hard bargain for both sides, admittedly, but one worth pursuing.

As late as 1998, John McDonnell was complaining that 'an assembly is not what people have laid down their lives for over thirty years. We want peace [sic], but the settlement must be just and the settlement must be for an agreed and united Ireland'. It is worth dwelling on this for a moment. McDonnell took a harder line than Gerry Adams and Martin McGuinness.

Rhetorically, at least, he was closer to dissident republicans than the Sinn Fein mainstream. Five years later McDonnell claimed 'The peace we have now is due to the action of the IRA' which, in addition to being an untruth, ignores the responsibility the provisionals had for the war too.

But isn’t all this ancient history? Shouldn’t Corbyn and his colleagues on the far-left be granted an indulgence because it was all so long ago? Some people plainly believe so. These were not merely youthful indiscretions, or student misjudgements of the sort from which most people graduate, however. We are talking about a time when Jeremy Corbyn was already a member of parliament, a time when John McDonnell was a member of the GLC, a time when Diane Abbott was a rising star within London Labour.

To argue this means nothing is to maintain that Corbyn’s record is of no account, that his past actions and beliefs say nothing about him or offer no reliable guide to the kind of government he would run were he ever trusted to do so. It is, if we are being charitable, to say that Corbyn’s childhood lasted well into adulthood and that he should not be held to the same standard as other politicians. Because it is not as though he has 'moved on' or recanted his past support for violent republicanism.

Even now, he cannot fully do so. When asked if he condemns IRA violence he offers the platitude that he condemns 'all' violence. This is the same kind of cant produced by appalling American conservatives who, when asked about Black Lives Matter, gravely intone that actually 'all lives matter'. The response is revealing.

There was never anything reprehensible about seeking a united Ireland provided that it was sought by peaceful means. Labour’s policy in the 1980s was for Irish unity by consent. That troubled Unionists, for sure, but it was also something rejected by Corbyn and his allies on the far-left. Even today, the likes of Ken Livingstone continue to struggle with the consent principle; it was even worse back then. There was a choice, however, between decency and indecency, between peaceful politics and violence and Corbyn and his people chose indecently. They abetted, to put it kindly, the men of violence.

Perhaps you think this does not matter, that people who, to put it more generously than they deserve, indulged the murder of British soldiers and British civilians, should now be considered fit for the highest offices in the land. I disagree. I believe that the historical record matters and that it is no smear to insist that what actually happened was what actually happened. And shame on those who think otherwise, who argue that there’s nothing to see here, nothing to be concerned by, nothing that is in any way any kind of big deal. Nothing that tells us anything useful about Jeremy Corbyn.