The Swedish constitution allows the Prime Minister to appoint one of the Ministers in the cabinet as deputy prime minister, in case the Prime Minister for some reason is prevented from performing his or her duties. If a Deputy Prime Minister has not been appointed, the Minister in the cabinet who has served the longest time takes over as head of government. A Deputy Prime Minister can only serve as Prime Minister in a temporary function, as the resignation of a Prime Minister automatically includes the entire cabinet, and the Instrument of Government requires the Speaker of the Riksdag to dismiss the cabinet in the case of the death of the Prime Minister.
In 1986 Deputy Prime Minister Ingvar Carlsson became acting Prime Minister for the transitional cabinet from March 1 to March 12, upon the assassination of Olof Palme, the only time the death of the Prime Minister has caused the Deputy Prime Minister to temporarily assume the office. Carlsson subsequently received the task of forming a new cabinet from the Speaker of the Riksdag. The cabinet was approved by the Riksdag on March 12, 1986, effectively reappointing most cabinet members in their previous offices.
Role in coalition governments
The role and position of a Deputy Prime Minister may vary. In the five last coalition cabinets, Fälldin III, Bildt and Reinfeldt I and II, and Löfven, the Deputy Prime Minister was the head of the second-largest coalition partner. In the governments Fälldin I and II, however, the Deputy Prime Ministership belonged to the Liberal Party despite the fact that it was the smallest of the three members. The reason for this might be ascribed to an unwillingness on behalf of the Centre and Liberals to give this position to the Moderates, due to ideological differences. In all of these governments, however, the Deputy Prime Minister also had a regular Cabinet portfolio. In July 2015, the office of the Deputy Prime Minister was the subject of some political debate. Following a brief illness of the social democratic Prime Minister, Stefan Löfven, the Prime Minister's office revealed that the Deputy Prime Minister Åsa Romson of the Green Party, although named Vice statsminister when the cabinet took office in October 2014, was in fact not expected to temporarily assume the duties of the Prime Minister as Statsministerns ställföreträdare as stated in the Instrument of Government, instead yielding to the most senior minister of the cabinet. Effectively this makes social democratic Foreign Minister Margot Wallström the actual deputy of the Prime Minister, due to seniority rather than appointment. It also rendered the title of Vice statsminister an honorary title, for the most senior member of the party functioning as junior partner in the governing coalition, rather than an actual function.
Role in one-party governments
The situation is different in the one-party governments that have existed since the position of Deputy Prime Minister was introduced in 1976, namely the Liberal Ullsten government and the Social Democratic governments Palme II, Carlsson I-III and Persson. While Mona Sahlin might well have been described as something of a "successor-in-waiting", the other Deputy Prime Ministers have tended to be older and experienced politicians who have often been in charge of coordinating the work of the Government and may also have been in charge of some policy areas of their own which were not substantial enough to warrant a full-time Cabinet position, such as Bo Ringholm, who was Minister of Sport concurrently with being Deputy Prime Minister.
