Northern Ireland Secretary James Prior announced Monday that he wishes to leave Ulster by the autumn. His departure will put a question mark on the future of the Northern Ireland Assembly, which was largely his creation.
It may also delay any significant London moves on the New Ireland Forum, the controversial nationalist blueprint for Irish unity. A new secretary of state for Northern Ireland will need time to gauge the feel of complex Irish politics.
Mr. Prior's decision to go has been expressed privately in recent weeks. He chose to make it public on a BBC radio program from his Norfolk, England, constituency. He said: ''I think probably the time comes when a fresh mind ought to be brought in. I think I have probably done about as much as I am going to do.''
He went on: ''If you ask me about my next job, this is a matter for Mrs. Thatcher, and not for me. I would not be surprised if this was my last job in government.'' He thus indicated he would not join the small group of dissidents objecting strongly to Prime Minister Margaret Thatcher's economic policy.
His announcement is seen as a preemptive strike against any attempt to remove him from the Cabinet or offer him a job he would not accept.
Normally a politician of his stature would be retained in the Cabinet because he represents a small but significant group within the Conservative Party. With his announcement, Prior is in a position to preserve his dignity, whatever happens.
Prior is known for his liberal views and his belief that politics is the art of the possible, but in Ulster he faced politicians with entrenched views. His attempts at round-table talks failed to pierce the shell of bigotry and intolerance that is the legacy of Irish history.
His most ambitious project was the establishment of the Stormont Assembly to try to provide common ground for sectional politicians. But the mainly Roman Catholic Social Democratic and Labour Party argued that Protestant unionists would not share power. The SDLP pinned its hopes instead on an all-Ireland solution, eroding the effectiveness of the assembly from the start.
The flurry of political activity that established the assembly gave rise to Sinn Fein, the political wing of the outlawed Irish Republican Army, which now poses a direct challenge to the SDLP.
The other major development during Prior's stay has been the New Ireland Forum, an attempt by nationalist politicians in Dublin and the northern-based SDLP to work out a plan for Irish unity that would attract the north's 1 million Protestants. It produced three options: a unitary state, a federal Ireland, or joint sovereignty of Ulster by Britain and Ireland.
The plan was well-received in Britain, the Irish Republic, and the United States. But Northern Ireland unionists said the forum showed more of Irish rhetoric than realism.
They dismissed the three Dublin options as unworkable and pointed to a fourth - that the Ulster Protestants had the right to remain British.
Meanwhile marked differences of opinion surfaced among the nationalist politicians who had set up the forum.
The British position is that there can be no official London response to the forum until after the June 14 elections for the European Parliament.
Prior cannot point to political success in Ulster, but he cushioned the province from the worst effects of the recent recession. There has been an economic upturn, with more jobs for the Belfast shipyard and spectacular success for Shorts, the aircraft and missiles manufacturers.
On the security front Prior has not done badly, despite spectacular terrorist incidents that captured headlines. In 1982 there were 97 deaths; last year, 77.
In personal terms, Jim Prior and his wife, Jane, have been regarded as civilized, caring people who tried to do their best for all the people of Northern Ireland.