Last year Mr Tony Blair spoke of the "hand of history" being on his shoulder. If the current positive mood leads to progressive developments, the hand of history may pat him and others on the back.
The first indication that all was far from lost came on Sunday night with news that there were grounds for cautious optimism. It has since emerged that a meeting last Friday between the unionists and Sinn Fein went well.
Yesterday afternoon, eyebrows were raised when it was reported that a further meeting between unionists and republicans which started in mid-morning was still going on late in the afternoon. It was also a healthy sign, if a little disappointing for journalists, that unionist sources would not even reveal the time the meeting had ended but merely said it was "very businesslike".
Unionists have the name of being good business people and it looked at this stage as if some business was about to be done. The arrival of the two prime ministers did nothing to stop the gradual rise in expectations. Mr Ahern said: "If people are prepared to be flexible and creative we can move."
It had been said earlier that tomorrow lunchtime was the final deadline if the transfer of powers was to be completed by Westminster before Easter. Maybe it could be achieved.
Mr Blair also communicated a sense of what one might call "positive urgency". He said outside Hillsborough Castle: "We have come a very, very long way indeed and I can't believe we are now going to throw it all away. The cost of failure is too high - it always has been."
While an IRA source described the naming of the nine bodies of the disappeared which had been located as coincidental, it will be widely seen as an initiative that will have an effect on the peace process. There will be criticism and in some quarters outrage but others will see it as a positive move. The expression of regret will be dismissed by some but welcomed by others. It may not have a hugely positive effect but it will not do any harm and will come as a welcome relief for families that have suffered beyond all imagining.
One theory has it that the unionists will face a "reality check" on the weapons issue - there will be no "product" forthcoming in advance but there will be a commitment to peaceful means and to removing the guns, whoever holds them, from Northern Ireland for good. The choice for the unionists will then be to insist on guns now, even at the price of destroying the peace process and their own political futures.
The counter-scenario is that if Mr Trimble comes back without IRA guns, he will be devoured by his own party. It would take very little effort to secure an emergency meeting of the Ulster Unionist Council where his leadership would be challenged. On past figures he might well win that vote but sustain considerable collateral damage. The Assembly team, thanks no doubt to careful candidate selection, is a good deal more quiescent than the party at large but it is fortunate nonetheless that the establishment of the executive does not need to be approved by a vote of the Assembly: as a Dublin source put it: "The executive establishes itself."
We are no nearer to understanding what Mr Adams meant on Capitol Hill when he spoke of "stretching the republican constituency". One view is that he meant stretching the resources of the English language to come up with a reformulation of traditional republican ideology that would placate unionists without causing a split in his own ranks. Catholic, Protestant and Dissenter unite, you have nothing to lose but 30 years of conflict.
There have been some signs of a narrowing of differences. The weekend appearance by Sinn Fein's Mitchel McLaughlin and the UUP's Michael McGimpsey on Radio Ulster's Inside Politics was so civil and reasonable that one observer remarked: "If it was left up to those two, the problem would be solved by now."
Unionist insiders said they were sitting tight this week and waiting for the storm to blow over. We may be back to the policy of turning a "stone face" to suspect and danger-laden processes.
The problem with carrying the battle to the foe is that in the words of a Prussian general quoted recently by David Trimble: "No strategy survives contact with the enemy." But will Mr Blair allow the UUP to "sit tight?" Not very likely.
There is a problem for Mr Blair: in the past he has given undertakings on decommissioning which have now come back to haunt him. There is every likelihood that unionists are reminding him of these undertakings this week.
Dublin has also given hostages to fortune by appearing to back the unionist stance on decommissioning. The UUP has a record of those statements also. If the process collapses there will be recriminations and Dublin's stop-start line on weapons may form a central part of that debate.
The urgency of this week's events lies in the need to maintain momentum in the peace process. As one observer said, it will be "very cold porridge" by the time we come back after a summer of marches and probable mayhem. The Rosemary Nelson killing was a bad omen of what may develop further down the line.