Mr David Trimble leaves an honourable legacy that will stand the test of time in Anglo-Irish history.
Yet, it is fitting that the Ulster Unionist Party which he led for 10 years, some of them as First Minister of Northern Ireland in the first all-inclusive power-sharing Executive, should move swiftly to fill the vacancy caused by the announcement of his resignation.
He presided over extensive and unexpected losses by his party in the Westminster and local elections. There is an urgent requirement, at this time, for leadership, steady nerves and, above all, strategic planning for the future if the UUP, in its centenary year, is to survive.
Mr Trimble's departure from Northern politics will remove one of its most thoughtful, acerbic and courageous leaders. His early years saw him flirt with Vanguard and champion the right of the Orange Order to march on the Garvaghy Road. His reputation as a "hard man" brought him the leadership of the Ulster Unionist Party 10 years ago.
Times were changing. The Anglo-Irish Agreement was up for review. Paramilitary ceasefires had been called. And the two governments produced a framework document setting out a shared understanding of how political progress could be made through the ending of divisions and conflict. The document sketched a broad outline of what was to become the Belfast Agreement.
The Belfast Agreement could not have happened without Mr Trimble. He fought a hard battle in the negotiations with nationalism in Ireland. He secured changes in Articles 2 and 3 of the Constitution - always the bete noire of unionism - and secured, with John Hume, a template where the constitutional status of Northern Ireland could change only if a majority - not the majority - in the North wanted it.
With the Irish and British governments determined to move ahead and support coming from the United States and Europe, Mr Trimble found himself on shifting ground. In adapting to changed circumstances, he alienated traditionalists within his party. But he persevered in finding common ground and decent compromises with nationalists. Then, following security assurances from the British prime minister, Mr Tony Blair, he signed up to the Belfast Agreement in 1998.
There is no point in rehashing the political disagreements, misunderstandings and sheer bad faith that damaged confidence in the power-sharing Executive and in the agreement that had been endorsed by handsome majorities on both sides of the Border. But some of the key setbacks can be traced to the intransigence and continuing activities of the IRA.
Mr Trimble still supports the Belfast Agreement and regards it as his greatest political achievement. He always seemed a reluctant supporter of this accommodation. Unlike Mr Hume, his joint Nobel laureate, he did not articulate its vision. Yet, constitutional nationalism on the island will settle for no less. That is his legacy. The DUP is kidding itself if it thinks otherwise.