There was probably little in Senator George Mitchell's briefing for President Clinton on the state of play in the threatened peace process that the President did not know already.

The President has been closely following the long-drawn-out review process since it began in September. According to a well-informed observer here, he has been making telephone calls to key figures, but discreetly and usually getting aides to ensure first that he is not cutting across Senator Mitchell's efforts.

But the idea that the President is having to put any kind of pressure on Senator Mitchell to "stick with it", as one newspaper report put it, is dismissed in Washington as farfetched.

President Clinton, who first appointed Senator Mitchell to a diplomatic mission to Northern Ireland as far back as December 1994, knows there is no one now who is more experienced in the Byzantine politics of that corner of what he now calls "the land of my ancestors". Incidentally, Ireland is also for Senator Mitchell "the land of my ancestors" through his Kilroy forebears.

"George is very much his own man," a diplomat here says. "Understandably, he has an eye to his role in history. It would be a terrible anti-climax if all the achievements of the Good Friday agreement were to melt away."

So there would be no need for President Clinton to spur on his trusted emissary to greater efforts. Senator Mitchell is not going to see his crowning achievement of public life join the melancholy list of other failed efforts to bring lasting peace to Northern Ireland.

Peace for that troubled area is an important part of the political legacy of both men, in a way which neither could have foreseen five years ago when Senator Mitchell was sworn in as "special adviser to the President and the Secretary of State on economic initiatives in Ireland".

Since then he has chaired a commission on how to deal with paramilitary arms, the peace agreement negotiations and now the review of the stalled part of that agreement.

A failure in the peace process and a return to violence would be a humiliating blow to both men, who have rightly taken much credit for the Belfast agreement, but as the months have passed and increasing despondency has replaced the euphoria of that day, Senator Mitchell has had to return to the scene of his triumph to stave off disaster.

His description of the minutes preceding the signing of the Belfast Agreement in 1998 now have an ironic ring. "I entered the large meeting room as I had done hundreds of times before, but this time was different. This was the last time. This time there would be an agreement. The two governments and eight political parties were about to commit themselves to peace, political stability and reconciliation in Northern Ireland. My Irish journey was over."

Now he knows better.

Last April, as his book, Making Peace, was published, he told this correspondent that he found the rumbles that he might have to return to solve the crisis over decommissioning of IRA arms and the setting up of the power-sharing executive "not helpful".

Instead, he wanted the parties "to learn to work together and solve their problems by themselves".

"It is not helpful," he went on, "that people keep suggesting I come back because it can create recalcitrance among the participants. If they think negotiations are not really going to begin on each issue until I or someone else comes in from the outside, they are much less likely to be forthcoming and to be willing to compromise among themselves. I think that attitude has to change."

That was then.

In his statement last Tuesday after nine weeks of intensive talks, mainly with the UUP and Sinn Fein, Senator Mitchell was more bland. He is "convinced that these parties are sincere and acting in good faith in seeking the full implementation of the Good Friday agreement. They want devolution and decommissioning. The problem, of course, is that there are differences among the parties on how these objectives can be achieved."

Quite so.

Last night, Senator Mitchell told President Clinton how near he was to resolving these differences - or how far. The President will no doubt have ruefully recalled his own analogy for the impasse when he blurted out during a speech in Ottawa last month how the opposing parties were "like a couple of drunks walking out of the bar for the last time. When they get to the swinging door, they turn right around and go back in and say `I just can't quite get there'."

It may have been "inappropriate" language, as the President said in his swift apology, but the frustration and the "fatigue factor" it reflected were well understood by all those who want the process to succeed.

To pursue the analogy, Senator Mitchell now has to get Sinn Fein's Gerry Adams and the UUP's David Trimble through "the swinging door" or "over the line", as the Taoiseach, Mr Ahern, puts it in sporting parlance.

According to informed thinking here, President Clinton will be strongly encouraging Senator Mitchell to stay with the peace process in the way he has already decided to do himself. Whether this means a "more detached" engagement in the continuing talks to resolve the decommissioning impasse or long distance "tele-management" remains to be seen. The important thing is that "failure" must remain unthinkable.

By coincidence, Mr Trimble will also be visiting the White House this week, two days after Senator Mitchell. It is a coincidence as the visit has been tagged on to a longstanding arrangement for Mr Trimble to give a lecture on the peace process to Ball State University in Indiana.

The UUP leader is to meet President Clinton's principal adviser on Northern Ireland, Mr Jim Stein berg, tomorrow. There is always the possibility on visits like these that the President can "drop by" for an informal chat.

Given the critical point reached in the peace process, it will be tempting for the President to take advantage of Mr Trimble being under his roof. On the other hand, diplomatic observers see a problem of "even-handedness" if the UUP gets a presidential face-to-face and not Sinn Fein.

But if President Clinton believes he can secure the legacy for himself and Senator Mitchell by some words in Mr Trimble's ear, he will do it.