Despite his repeated assertions that he is himself a Unionist, the framework document he unveiled on Wednesday was a comprehensive and undisguised rejection of all the principal Unionist political theories. It blasted them out of the water, opting instead not for a united Ireland but for an all-Ireland approach.
British governments have produced many documents to balance demands of Unionist and nationalist politicians, but this was not one. Although the surrounding rhetoric aims mostly at soothing Unionists, the actual text of the document contained no attempt at symmetry.
Northern Ireland is not to have joint authority, if what is meant by that is 50-50 rule by London and Dublin, and it is to remain in the union. But the terms of that union are to be changed to introduce a new dispensation with a whole new philosophy and system of government.
In deciding on this course, Mr Major walks in the footsteps of Margaret Thatcher, who began by asserting that "Northern Ireland is as British as Finchley" and wound up being burned in effigy by loyalists for signing the Anglo-Irish agreement.
Why did Mr Major, who should be anxious to have the nine Ulster Unionist MPs supporting him in the Commons, come to reject so decisively the policies of Unionist leader James Molyneaux? The answer lies in the fact that unionism's arguments and vision were carefully considered and found wanting.
The basic proposition of the two governments is that it is axiomatic that a lasting settlement will not come about without an inclusive new system of government to which everyone, or almost everyone, can give their allegiance.
The Rev Ian Paisley, with his appetite for discord and division, has clearly never been in the business of helping construct such a system. Between Mr Paisley and Mr Molyneaux are substantial differences of style and content, not to mention volume, but there are also many points of similarity.
Neither has any sign of an equality agenda, and neither shows any sign of producing an offer which stands a chance of meeting the concerns of even moderate nationalists. Neither is thinking of working towards an agreed political settlement; and neither is going to do a deal capable of making nationalists feel at home in Northern Ireland.
In the past, this intransigence was obscured by the IRA's terrorism, but since the ceasefires, the question of a willingness to compromise has assumed central importance. Out in the Protestant community, things are stirring and attitudes are being re-examined, but this has not been reflected by the Unionist MPs. The opposite has been the case. All along, they predicted the peace process would come to nothing, with Mr Molyneaux a year ago describing it as "a dead Christmas tree". Far from welcoming the cessations, they regarded them as problematic, leading many to suspect they almost preferred the old certainties of conflict. One MP complained recently: "We've been outflanked by peace."
In short, the approach of the Unionist politicians bears no promise of leading towards an inclusive settlement. On the other hand, there has been a persuasive set of arguments coming from nationalists.
For more than two decades, nationalist theoreticians such as Garret FitzGerald and John Hume have accepted that Irish unity could only come about with the consent of a majority in Northern Ireland. (Consent was the buzzword of the week: it occurs in the framework document at least 10 times.) This approach shifted the focus away from the idea of pursuing the territorial unity of Ireland towards that of reconciling its differing traditions.
This theory superseded the traditional nationalist belief that the British presence was the root cause of the problem, and thus made it easier for Dublin and London to co-operate. The continuing violence had the effect of bringing the British and Irish establishments closer together, the 1985 Anglo-Irish agreement demonstrating their growing sense of partnership. The two governments came to regard Northern Ireland as a problem best jointly managed.
Another strong factor was that, viewed from London, the south was becoming a steadily less threatening place. The power of the Catholic church has been draining away for years, while the intelligentsia has placed more and more store on the rights of Unionists. Dublin is a cosmopolitan European city, where European unity is spoken of far more often than Irish unity.
All this made Britain more responsive to the argument that, in return for the ever more open acknowledgement of the consent principle, formal recognition was needed of the Irish aspiration of those 39 per cent of Northern Ireland voters who support nationalist parties.
This was true even as the violence raged, and indeed those involved in drawing up the framework document say it was scarcely changed at all after last year's cessations. But the ending of violence has created almost universal pressure for compromise and new beginnings, since the changed circumstances mean it is not just purely theoretical but also a means of consolidating the peace.
The immobilism of the Unionist MPs this week led to their isolation in the Commons, as they refused to join the consensus that a truly historic opportunity for peace exists if, as seems possible, the nationalist community coalesces around the notion of change by peaceful means.
The reaction of the general Protestant community has not been so unremittingly negative. The old cry of sell-out is still heard, but so too are Protestant voices saying that the tide is moving, that the time has come to negotiate the best deal they can; that in the cause of peace, they can live with something along the lines of the framework document. Such sentiments look like the first small signs that, this week, John Major has indeed caught the tide of history.