This is a familiar pattern, in that the early days of talks tend to be dominated by posturing rather than detailed negotiation. So while the various sides seem as far apart as ever there is an expectation that the review will at some stage evolve into a serious and determined effort at breakthrough.
Although, as Senator Mitchell once remarked, "the political pull in Northern Ireland is not toward the centre but away from it", it is none the less the case that there are forces impelling the two sides towards agreement. Failure would lead in time to the suspension or closure of the Belfast assembly, which would be a huge blow to hopes that a cross- community government could ever exist.
For some politicians this would mean not just a political but a financial setback, given that their salaries and expenses would presumably stop. Some of those politicians who instinctively favour a hard line may therefore be given pause for thought before going along with a course leading to a substantial loss of income.
Such mundane but important considerations may well give the senator something to work on. Senator Mitchell's presence itself has real significance. His return makes the point that the United States has its own commitment to the peace process, with President Clinton remaining closely involved and pressing for a resolution. The senator may be in the business of pointing out, however, that the continuing interest and goodwill of America cannot be taken for granted.
A President George W Bush, for example, is unlikely to devote the energies and time to the Belfast peace process that Bill Clinton has done. This probably is true for the rest of the world as well, for indefinite stalemate is likely to prove an international turn-off.
This is not to say flatly that the review is the last chance. Failure would be a blow, but the British and Irish governments have realistically little alternative but to keep trying. This does not however apply to Senator Mitchell himself, or to the United States or the wider world, all of which have the option of concluding that the Irish problem is intractable and sadly walking away from it.
Thus while the senator will not be in the business of delivering ultimatums, he can be expected to spell out that the present window of opportunity will not remain open for ever. Both sides have their hardliners to worry about: his message may be that if there is to be a breakthrough the political leaders will need to take yet more risks for peace.