During his long career in Danish politics, Nielson served as
Energy Minister in the
fourth and
fifth cabinets of
Prime Minister Anker Jørgensen from 26 October 1979 to 10 September 1982, and as
Minister for Development Cooperation in the
Cabinet of Poul Nyrup Rasmussen II,
III, and
IV from 27 September 1994 to 10 July 1999. By the time he left office, he was the EU's longest-serving development minister. In 1999, he was also the EU's official candidate for leading the
United Nations Development Programme (UNDP); the post instead went to
Mark Malloch Brown. On 17 September 1999 Nielson became
European Commissioner for Development and Humanitarian Aid when the
Prodi Commission took office. Early in his tenure, the EU signed the
Cotonou Agreement with its 71 partners from the
African, Caribbean and Pacific Group of States (ACP) which put relations between Europe and its former colonies on a new footing for the following 20 years. In 2002, Nielson and
Margot Wallström led the European Commission's team at the
World Summit on Sustainable Development. In response to what later became known as the 'decency gap' left by US President
George W. Bush's controversial refusal to release funds already approved by Congress, Nielson also led efforts for the EU to pledge additional support for the
United Nations Population Fund (UNFPA) in 2004. ==Life after politics==