The referendum campaign in Scotland has been far too introverted.

I've just spent a few days in Ireland, first in Belfast and then in Dublin, and I've been reminded of just how strong the ramifications of our decision could be beyond Scotland.

In Northern Ireland, needless to say, the Unionists dread a Yes vote, or even a close No vote. They sense that either of these outcomes would be seized on by Irish nationalists as a huge blow to the integrity and continuing feasibility of the Union. And the Unionists are right. The Union is probably more important to them than it is to any other political community within the UK, and it is under threat.

In the south, the situation is more complex, not least because the Irish seem to be enjoying a quite extraordinary love-in with the British state, and England in particular.

Centuries of bitterness and conflict cannot be expunged by one brief visit, yet there can be little doubt that the Queen's trip to Ireland three years ago was hugely important for the Irish people. In particular the way she very publicly paid homage to the Republican dead was seen as marking the end of a long and fraught chapter, and more importantly the beginning of a much brighter new one.

Where does Scotland come into this? Well, there is - and this amazed me - a feeling in Dublin that if Scotland were to quit the Union then Ireland might just step into the gap. Of course there is no possibility whatsoever of any kind of formal linking of Ireland and England. That would be absurd. But there are those in Ireland who think there could soon be a much closer and stronger bond between the two countries.

This feeling will be symbolised next Monday when the Irish President Michael D Higgins - a genuine man of the people who used to be something of a political firebrand, to put it gently - and his wife Sabina arrive at Windsor Castle for the first full state visit by an Irish leader to Britain. I say Britain, but while Mr Higgins and his wife will have a very busy schedule, they will come nowhere near Scotland, or even the north of England.

I reckon that the geographic restrictions of the visit are highly significant. Mr and Mrs Higgins will be confined to the south and the midlands; the furthest north they will get is Coventry, where the President will inspect the war-damaged ruins of the old Coventry cathedral.

When the schedule of the visit was released last Thursday, I suspect that few people in the UK noticed. In Dublin, however, there was genuine excitement. The details were picked over with fascination and pleasure. While President Higgins will address both Houses of the UK Parliament, this is regarded as being less powerfully resonant than another, more sensitive part of the visit: his inspection of the colours of the various disbanded Irish regiments. For reasons that I confess I don't fully understand this will apparently be the moment of the greatest historical and symbolic significance - the equivalent, indeed, of the Queen bowing in respect to the Republican dead three years ago.

The word respect is greatly overused, but I think it was valid then and it is valid now. What is happening is that the Irish sense that at long, long last the British - or in this case the English - are showing them due respect. They are grateful for this, and they want to seize on it and build on it. A Yes vote in the Scottish referendum would give them a very neat opportunity to do so.

But it would be wrong to suggest that all the old wounds and grievances are being forgotten. Indeed there is going to be much reflecting, in exactly two years' time, on the Easter Rising in Dublin in 1916. This was a minor event, considering that the First World War was continuing in all its horror on the continent, yet its political residue remains potent. Patrick Pearse, the very eloquent leader of the rebellion, gave it an almost religious resonance. The oft-repeated phrase of the time "I believe in the Irish Nation" had echoes of the start of the Apostle's Creed, and Pearse (himself a poet) wanted to reinvent a Columban Ireland, stripped of English capitalism, industrialism and exploitation.

Last week in one Dublin bookshop I found no fewer that 15 different books dealing with various aspects of the rising, when, in the famous words of WB Yeats, "a terrible beauty was born". I understand that several more books are planned.

The actual revolt, led by Pearse and the Irish-Scottish socialist James Connolly, was put down by British soldiers in less than a week. What gave it resonance, still strong after 98 years, was the unnecessary and indeed vicious reprisals that followed. The leading rebels, who had surrendered, were executed, with one exception: Eamon de Valera, who went on to be president of his country. Thousands of others were imprisoned or deported.

The rising itself was a total failure; there has since been speculation that its timing was both opportunistic and premature. Had it taken place three years later, when the First World War was over and Europe was broken and dispirited, it could have triggered revolts, even revolutions, elsewhere.

When the Irish did eventually gain their independence, the first years were difficult, and the Irish state was more conservative and cautious than some had expected. It was not just British rule that had been broken. There was also a sense, as Pearse had carefully anticipated, that English (not British) culture had to be rejected and Irishness had to be reinvented.

Whether that has been achieved or not is even now still open for debate. What has undoubtedly been achieved, however, is political maturity. The Irish are not disposed to defer to anyone or any state. In their current dealings with Britain, the Irish see themselves as equals, and more importantly they feel that they are being treated as equals.

Those of us who are contending for an independent Scotland should surely have a good hard look at Ireland, and all the lessons that have been learned, some of them no doubt painful. The Irish state has had many ups and downs, as well as illusions, such as the much- mocked "Celtic tiger".

It should probably not have remained neutral throughout the Second World War when its neighbour Britain was fighting desperately against the most evil regime in world history. Nor should President de Valera have expressed his condolences on Hitler's death. It was almost devastated by the financial crisis of six years ago, and it still has its scars and divisions. Many people in Dublin live wretched lives.

But Ireland has survived and while there are grotesque disparities, as in most European nations, it strikes me as country that is self assured, flexible and now capable of creating far more than a terrible beauty.