The McCartney family's campaign has been hugely successful, although the backbiting has already begun back home, writes Mark Hennessy, Political Correspondent
Like so many others in Ireland, the McCartneys grew up with the Child of Prague on the mantelpiece, the picture of the Sacred Heart on the left, the picture of slain US president, John F Kennedy on the right.
Sitting in Senator Ted Kennedy's Capitol Hill office on Wednesday, Gemma, one of the five sisters of Robert McCartney, told him how their mother Donna had idolised the youthful president.
"What's her number," quipped Kennedy, who knows more than most about losing siblings at the hands of violent men, before he reached for the telephone and rang Mrs McCartney in Belfast.
Such are the changes that have taken place in the lives of the women ever since their brother was murdered in late January.
Whereas the road to Washington has been long and painful, the road home for the five women and Mr McCartney's partner, Bridgeen Hagans, is paved with even more difficulties.
The backbiting has already begun, particularly after images of the women attending the American-Ireland Fund dinner on Wednesday night were shown on UTV and the BBC. "Do you know what they are calling them already in Belfast," one Northern journalist said sadly, "The Corrs".
Though the campaign for justice launched by the women has been successful beyond their wildest dreams, few looking on believe that a successful prosecution, for murder at any rate, will ever be brought.
However, the six, who have endured a crash course in the media and high politics in recent weeks, have repeatedly been underestimated and have proved their critics wrong.
"There will be a minority of people who will feel that we shouldn't be doing what we are doing. But they should ask themselves what would they do. Would they not fight for justice?" asked Catherine McCartney yesterday.
The McCartneys presence in the United States has done serious damage to Sinn Féin's reputation, even though the family has not tried to pick a fight with Gerry Adams, or others.
"Sinn Féin have been the ones to inflict the damage on themselves, not the McCartneys," SDLP leader Mark Durkan said yesterday afternoon as he prepared to leave Washington.
Unlike so many other stories out of Ireland, the death of Robert McCartney is a simple, if horrible, one. There was a brutal killing, there was a cover-up, and there were denials, evasions and lies.
Though the upper reaches of establishment Irish-America closed its doors this week to the Sinn Féin leader Gerry Adams, he and Martin McGuinness and others are still trusted deeply by many.
Indeed, the speech made by Republican senator John McCain on Wednesday night, when he condemned Sinn Féin and described the IRA "as nothing better than a criminal syndicate", has caused fury.
On Thursday morning members of Friends of Sinn Féin were still livid when they gathered for a breakfast meeting with Mr Adams. "I got to bed at 3am. I was still raging with that bastard," said one man.
However, Irish-American opinion has changed radically since 9/11. In times past, many would have been happy to shout "Up The 'Ra" openly and put their hands in their pocket for "the Struggle".
Today, most, bar the dimmest, realise that those days are over.
In Boston recently, Sinn Féin's Alex Maskey faced tough questioning when he attended a meeting with blue-collar Irish-Americans.
"What are you doing to us, Alex?" one demanded.
Nevertheless, Irish-America will be slow to close the door completely on Adams, if only because they have invested so much of their own faith in him.
If Adams has lied, then their own judgment will be called into question.
But patience is wearing thin. Irish-Americans were slow to believe the charge that the IRA was involved in the Northern Bank raid. Some still do not, but most have been persuaded otherwise.
If evidence is produced, and convictions are ever imposed on IRA members then Adams's credibility will have been fatally damaged.
However, convictions in cases such as these are slow to come.Further robberies or further killings will make his presence in the United States intolerable, particularly when some, including the British embassy in the US, are already comparing him with Yasser Arafat.
Such a charge, if it ever stuck, and it has not yet, would end his credibility with a US audience still seared by the memory of 9/11 and the loss of their feeling of invulnerability.
In January the US special envoy to Northern Ireland, Mitchell Reiss, took questions from journalists after a meeting with Minister for Foreign Affairs Dermot Ahern.
"One woman from Fox News asked: "Would we be letting these people in if they were Arabs."
"Reiss nearly died at the microphone," said one witness to the envoy's discomfiture.
However, the McCartney case and the frenzy of this week will eventually fade from people's memory in the US, as journalists and time move on.
Sinn Féin is depending heavily on that happening.
Although the McCartneys have delivered a simple message well and often this week, they will have been wise to note the presence of two other women in Washington, Geraldine Finucane and Ann McCabe.
Sixteen years on, the British government is still refusing to hold a full public inquiry into the 1989 murder of Belfast solicitor Pat Finucane.
Ann McCabe, on the other hand, has seen men convicted, but for manslaughter and not murder of her husband, while she has also had to repeatedly contend with the prospect that they could be released early.
Neither has seen justice in their eyes.