A former US ambassador to London, Raymond Seitz, called her "too shallow to understand the past and too naive to anticipate the future". But after yesterday's agreement Jean Kennedy Smith may go into history as the most effective ambassador to Ireland Washington has yet had.
Whatever about that verdict, she seems to have had the last laugh on Seitz. In his memoirs, published earlier this year, he also called her "an ardent IRA apologist" and said her 1993 appointment to the Dublin embassy was "a curious selection, not because of [her] inexperience, but because she was both wilful and skittish, a dangerous mix."
If this was the disinterested judgment of a career diplomat, it also had the flavour of sour grapes. There is little doubt that Seitz's opinion was at least coloured by the shift in influence away from London, where he was US ambassador between 1991 and 1994, to Dublin, when Mrs Kennedy Smith arrived in 1993.
His was not the only nose put out of joint by the move. During the controversy over the Gerry Adams visa in January 1994 senior embassy staff in Dublin dissented from the new ambassador's support for the visa, cabling Washington to that effect. The incident, and subsequent allegations of reprisals against the staff in question, were to be the subject of a 1995 inquiry by the US State Department.
The visa incident confirmed what everybody involved knew by then, that times had changed in Washington's Dublin mission. Until the Clinton administration, Ireland had been a sleepy outpost in US diplomacy, little more than a retirement perk for supporters of the White House incumbent.
The last Republican appointment, the octogenarian William Fitzgerald, had spoken at his confirmation hearings of "loyalists and unionists" being the opposing sides in Northern Ireland. Not that such a poor grasp of reality mattered, because the North had traditionally been off limits for the Dublin appointees.
But by 1993 two dramatically new circumstances were in effect: the end of the Cold War had lessened US need for a special relationship with Britain; and the White House had acquired a President with a real interest in Ireland.
Mrs Kennedy Smith was poised to take advantage of both facts. With President Clinton unable to refuse her brother Ted, she was assured of the job over other such Irish-American worthies as Congressman Brian Donnelly. But doubts persisted about her abilities: and a low-key performance at her Senate committee confirmation supported the view that she would be a mere puppet in Dublin for her brother.
From the moment of her arrival, however, the style and direction of embassy policy changed. For a start, under Mrs Kennedy Smith the Phoenix Park residence became an open house, for everything from charity events to political dinners to receptions for groups from all sides of the political argument, North and South.
In her own social life the ambassador immersed herself in the world of Irish arts and entertainment, mixing with a milieu which included the Sheridan brothers, Neil Jordan, Paul McGuinness and Louis le Brocquy, and even taking a walk-on part in Jordan's film, Michael Collins.
But this same energy and enthusiasm for all things Irish ruffled feathers in the embassy. The State Department report would later speak of a Dublin mission more attuned to Irish than US interests. It also complained that her "very heavy travel and entertainment schedule" excluded embassy officials, and her "very demanding" nature left staff "constantly nervous, tense and edgy".
With the Adams visa controversy in 1994, her relationship both with staff and the London embassy reached a flashpoint. And it reached another in August 1994 when, as part of the price for a ceasefire, Sinn Fein sought a visa to allow the veteran IRA man Joe Cahill to explain developments to American supporters.
The ambassador was the driving force behind the Cahill visa, telephoning a reluctant Nancy Soderberg, the National Security Council's Ireland specialist, first in Madrid and later in Los Angeles, to press the case. She also advised Albert Reynolds to play on Nancy Soderberg's Irish roots, in the same cause. Soderberg relented; President Clinton duly authorised the visa, and within hours the ceasefire had been delivered.
With yesterday's agreement, all the risks seem to have paid off and, from a notoriously male-dominated family, the outgoing ambassador may have made her mark as the first Kennedy woman to create a bit of political history.
On her arrival in Dublin, Mrs Kennedy Smith brought with her a photograph of her nomination ceremony, with an inscription from her brother Ted. The message was a poignant reference to an unfulfilled pledge by the late President Kennedy as he left Ireland in 1963. It read: "For Jean, who is going back in the springtime".
As she leaves Ireland this summer, Mrs Kennedy Smith can reflect happily on five years in which she delivered on an old family promise.