The fate of the Belfast Agreement will hang over the hectic round of meetings and dinners marking this year's St Patrick's Day celebrations in the US capital.
President Clinton has set the tone by issuing a special St Patrick's Day message from his birthplace in Hope, Arkansas, reminding Irish visitors of the "resolve to approach differences not with weapons but with words".
The President will receive the traditional bowl of shamrock from the Taoiseach, Mr Ahern, on St Patrick's Day at the White House and will host a reception for almost 1,000 guests when he presents Senator George Mitchell with the Presidential Medal of Honour.
The Taoiseach flies into Washington this evening from California. In New York, Senator Mitchell will receive the Irish-American of the Year award of the Irish Voice.
At the US Department of Commerce, the North's First Minister, Mr David Trimble, and Deputy First Minister, Mr Seamus Mallon, will attend an announcement by the Industrial Development Board of Northern Ireland of a major investment in Belfast by User Technology Associates from Arlington, Virginia.
The SDLP leader, Mr John Hume, will be discussing his book A New Ireland: Politics, Peace and Reconciliation at the National Archives in Washington.
Tomorrow the Northern Ireland political leaders and the Belfast media arrive. The Northern Secretary, Dr Mo Mowlam, kicks off early with a breakfast address in the Omni-Shoreham Hotel on the next steps in the peace process and receives an award for her contribution.
The Taoiseach will have a meeting at the State Department with the Secretary of State, Ms Madeleine Albright, and will later go to Capitol Hill to meet Senator Edward Kennedy and other members of Congress.
At the British embassy there will be what has become a traditional eve of St Patrick's Day lunch for the visiting Northern Ireland politicians.
The day will end with the America Ireland Fund black tie dinner honouring Senator Kennedy at the National Building Museum.
At a breakfast on St Patrick's morning, Vice-President Al Gore will be endorsed for the 2000 Presidential election by the Irish-American Democrats at the Capital Hilton Hotel.
On Capitol Hill there will be the traditional lunch hosted by Speaker Dennis Hastert and attended by President Clinton, the Taoiseach, the Northern Ireland leaders and members of Congress.
Snow fell as the Washington St Patrick's Day Parade took several hours yesterday to pass along Constitution Avenue and before the reviewing stand at the Ellipse near the White House.
The Grand Marshal this year was the New York policeman, Mr Denis Mulcahy, who was born in Rockchapel, Co Cork. He was being honoured for his work in setting up Project Ireland, which has brought several thousand children from Northern Ireland for holidays in the US. "Gael of the Year" at the parade was Mr John Cosgrove, former journalist and president of the National Press Club, who has been involved in most Irish-American events in the capital for the past 50 years.