After being barred from the annual White House St Patrick's Day reception for the first time in 10 years, Sinn Féin leader Gerry Adams is also likely to be excluded from the annual speaker's lunch on Capitol Hill, according to sources in the US Republican Party.
Meanwhile EU ambassador to Washington and former taoiseach John Bruton said on US television that Mr Adams was a leader of the IRA and warned that it would be "very, very dangerous" for the Republic if Sinn Féin were to hold the balance of power in the Dáil while tied to a secret army.
If Mr Adams is excluded from the speaker's lunch it will be another indication of a hardening sentiment in the US - among allies and critics alike - against Sinn Féin's continued association with the IRA.
House speaker Dennis Hastert, a Republican from Illinois, could not be reached for comment last night, but he is expected to follow the White House precedent in excluding Mr Adams from the March 16th event.
The lunch has become an occasion for the Taoiseach, leading Irish-Americans and Irish party leaders to celebrate St Patrick's Day together on Capitol Hill.
Mr Adams has been a regular guest since 1995 when speaker Newt Gingrich was compelled to include him because President Bill Clinton had invited the Sinn Féin leader for the first time to his White House St Patrick's Day reception.
Sen Edward Kennedy said the president had the right to determine his schedule "and it's the speaker's decision about who will be at the lunch".
In a statement at the weekend which reflected the growing exasperation of Irish-American supporters of the peace process, Mr Kennedy said: "There is no place for a paramilitary organisation and criminal activity in a democratic political party, and I will tell Gerry Adams that".
In an interview with John McLaughlin on the One on One programme on NBC and PBS, Mr Bruton replied "Yes" when asked if he believed Mr Adams was in the top leadership of the IRA.
"We are at risk in Ireland of seeing a Sinn Féin party which is closely linked with a criminal organisation - the IRA is very similar to the Mafia - that we are having mafia-influenced politics being introduced into the Dáil, into our parliament," Mr Bruton said.
"And they want to be in government or they want to hold the balance of power in the Dáil, and that would be very, very dangerous for Ireland."
He said that Ireland had become one of the most successful states in Europe on the basis of being a transparent democracy, but if politicians in power had a secret army calling the shots, "you wouldn't have the sort of confidence to attract investment into Ireland that you've had".
Mr Adams is due to begin a tour of US cities next Sunday and will attend the annual American-Ireland Fund dinner in Washington on March 16th, along with Taoiseach Bertie Ahern and leading members of both parties on Capitol Hill.