10 March 2005, the House of Commons in London passed without significant opposition a motion, introduced by the British government, to withdraw the allowances of the four Sinn Féin MPs for one year, in response to the Northern Bank Robbery. This measure cost the party approximately £400,000. However, the debate prior to the vote mainly surrounded the more recent events connected with the murder of Robert McCartney. Conservatives and unionists put down amendments to have the Sinn Féin MPs evicted from their offices at the House of Commons but these were defeated. In March 2005, Mitchell Reiss, the United States Special Envoy for Northern Ireland, condemned the party's links to the IRA, saying "it is hard to understand how a European country in the year 2005 can have a private army associated with a political party". The October 2015 Assessment on Paramilitary Groups in Northern Ireland concluded that the Provisional IRA still existed "in a much reduced form", and that some IRA members believed its Army Council oversaw both the IRA and Sinn Féin, although it believed that the leadership "remains committed to the peace process and its aim of achieving a united Ireland by political means". Organisation and structure Sinn Féin operates under the principle of Democratic Centralism; the concept that policy should be debated internally within the party, and once a decision is made, all members must support the chosen policy publically or be disciplined. Once a decision has been made, it cannot be revisited or altered for a prolonged period of time. Decision-making within Sinn Féin is controlled by two bodies; the national officer board and the Árd Comhairle (national executive). The national officer board consists of 7 members, made up of the President of Sinn Féin, the Vice President, the Chairperson, the General Secretary, the Director of Publicity and two treasurers. Policy will be debated amongst the national officer board before next being brought before the Árd Comhairle. Sinn Féin's Árd Comhairle consists of 47 members. Members of the national officer board are automatically members, while the rest of the membership is made up of officers elected at Sinn Féin's annual national conference (Ard Fheis). Members of the Árd Comhairle must already be members of the Comhairlí Limistéir (Area councils), which are based county or constituency boundaries. , despite the fact that the bulk majority of Sinn Féin's membership and elected representatives come from the Republic