Elections and referendums reflect changes that have happened already - and help to set the tone for change to come. Some of the changes that led to the Belfast Agreement and its emphatic endorsement in Northern Ireland and the Republic were less dramatic than the announcement of the results.
They could hardly have been more so. After all, popular support for the agreement, North and South, among unionists and nationalists, ranged from highly satisfactory to all but unanimous.
Here, taking shape before our eyes, was a framework for new relationships, in Northern Ireland, between Northern Ireland and the Republic and between the Republic and Britain. Articles 2 and 3 of the Constitution, long considered unalterable, were changed, radically; the principle of consent acknowledged all round.
Remember the grudging descriptions once applied to Northern Ireland: the Six Counties, a failed political entity. Remember how, in the North, any reference to unity was considered at best foolish, at worst seditious, always threatening. Now campaigns for unity or the maintenance of the Union may continue, free of any threat to those who oppose them.
All of this and much more had been agreed. Now it was adopted, with acclamation. The Republic's endorsement, by a majority of more than 15 to one (94 per cent to 6), was on a scale rarely experienced outside one-party states.
Though the latest Irish Times/MRBI polls had clearly indicated what was in store, the results still arrived with a jolt. This was more than all but the most enthusiastic pro-agreement campaigners had dared to expect.
Garret FitzGerald put it in historical context - "one of the great moments of Irish history; we've had 1916 and the Treaty and now this."
Brian Lenihan was impressed that, "for the first time since Gladstone introduced his Home Rule Bill (at the end of the 19th century), the vote didn't break down along sectarian lines." John Bruton saw the biggest Northern turnout at any election or referendum - 81 per cent - as "one of the greatest exercises in democracy anywhere in the world."
Interviewers casting about for a convenient problem with which to get a debate going found themselves at a loss. The only takers were those who wanted to re-run the campaign or explain that 71 per cent of the Northern electorate wasn't really a majority.
Bertie Ahern, Tony Blair and Bill Clinton congratulated each other and John Hume; those attending her press conference applauded Mo Mowlam; almost everyone - with the exception of some fellow unionists - praised David Trimble.
And Gerry Fitt, who's been working for reconciliation and co-operation longer than most of the modern leaders can remember, wished he'd had David Ervine and Billy Hutchinson to work with when he was in charge. (They were otherwise engaged.)
Lord Fitt was impressed too by the changes Gerry Adams had wrought in Sinn Fein. He hoped Mr Adams would continue to guide the party as he had done in what Mitchel McLaughlin called "this unique coalition of political forces on the Yes."
No one should be curmudgeonly enough to begrudge the politicians of all shades their moment of celebration. For most, like Monica McWlliams and her allies in the Women's Coalition it would be no more than a moment - at best a day out before the next campaign, which has already begun.
"Ireland has changed," said Seamus Mallon, "nothing will ever be the same again." He, more than most, understands how hope, fear and weariness played a part in changing the minds of people powerfully influenced by violence. Those who campaigned for the agreement raised hope; their opponents raised suspicion and some who voted No had good reason to be afraid. It will be for the paramilitaries and their political allies to persuade the fearful that they understand their fears and will do what they can to remove them.
It's a challenge with which they will be faced as soon as the campaign for seats in the assembly begins and will become acute, if it hasn't been resolved beforehand, when the newly elected assembly chooses executive.
Last week's doubts have left no room for uncertainty; when the people of Ireland, or any part of it, determine their future, they insist on doing it without the use of force.
Those who voted No in the Northern referendum must for the time being be considered a new minority and, as Mr Hume suggested on Saturday, approached with sensitivity - something which has often been denied to majorities in Ireland.
Politics has been revitalised by last week's decisions. Before the agreement, there was a feeling that the long-frustrated desire for peace was turning to despair and a loss of trust in politicians; indeed, a rejection of everyone involved in or associated with public life.
Brave attempts, from Sunningdale to Hillsborough, and a succession of well-meaning but flawed experiments - power sharing, rolling devolution, Anglo-Irish accords - went down in a welter of bitterness and recrimination, usually because some group felt excluded. The Ulster Workers' Council and the Provisional IRA smashed the powersharing executive, from which they'd been excluded.
Then, when trust in politics had all but vanished, discussions between John Hume and Gerry Adams promised change in the republican movement; John Major and Albert Reynolds struck a new note of optimism in the Downing Street Declaration and ceasefires were announced, first by the IRA, then by loyalist paramilitaries.
It was the first chance that many had had to enjoy life in the absence of full-scale campaigns of violence, which had already cost almost 3,500 deaths, 40,000 injuries and immeasurable disruption of the lives of many, many more.
Now that the people of the whole island have enjoyed, not just relative peace, but the prospect of making it permanent, their overwhelming approval has set a challenge for politicians, parties and governments.
It's a challenge that can't be refused.