After 8 years in opposition she led the Centre Party of Finland to a narrow victory over the formerly largest party, the Social Democratic Party of Finland. According to the new constitution, which was in effect for the first time after this election, she was thereby given the prime oppertunity to form a new Cabinet. After successful coalition negotiations with the Social Democrats and the Swedish People's Party, she came to head a Coalition Cabinet which chiefly continued on the lines of its predecessor, but introduced new measures to stimulate the economy, including tax cuts.
During her brief time in office Finland was the only country in Europe to have women as both prime minister and president, a situation underlined by the half of her cabinet being women, which however was quite in accordance with Finland's reputation as a country nurturing women's political contributions.
Annelie Jäätteenmäki's short term as Prime Minister for Finland is however not the shortest in the history of Finland. Beside caretaker cabinets and temporary prime ministers appointed due to death or disease of the predessor, Juho Heikki Vennola[?] headed a Cabinet which only lasted for one month and a few days in February-March 1931, in connection with the Lapua Movement's high-pitched anti-democratic demands for influence on the presidental election.
June 18, 2003, under pressure from the accusation that she'd lied to the Parliament and the public over how she'd acquired confidential Foreign Ministry documents used by herself during the election campaign. The documents contained diplomatic information from a meeting between USA's president George W. Bush and the then prime minister Paavo Lipponen about Finlands stand in the Iraq war. Jäätteenmäki used the information to suggest that her rival, the Social Democrat leader Paavo Lipponen, had secretly offered Finnish support for the US-led coalition, a substantial breach against the official policy of neutrality in foreign polics. Anneli Jäätteenmäki, on the other hand, thereby effectuated a substantial breach against the unity behind Finland's security policies, traditionally respected by all major politicians. As the elections turned out to be narrow, the defeated Social Democrats found reasons to suspect her untraditional campaign being decissive for the outcome, which made the two major coalition partners even sourer.
After the leaked documents were published in several newspapers in March, the police launched a criminal investigation on grounds of the official secrets act. On June 11th Prime Minister Anneli Jäätteenmäki was heard as a witness by the police, which lead to increasing pressure on her to come clear on her role in the leak. On the same week, the incriminating minutes of a meeting of Center Party leaders was leaked to the press, as later came clear, via the Center Party second vice-chairman Hannu Takkula[?]. On June 16th it came to light that the presidential aide Martti Manninen, affiliated with the Center Party, had leaked the Foreign Ministry documents. On June 18th, Mrs. Jäätteenmäki gave her "full explanation" to the Parliament and apologized to the President, claiming that she had been faxed the documents without asking for them, and that she had not known of their secrecy. The Parliament was not satisfied with her account, and once Mr. Manninen on the same afternoon publically claimed that Mrs. Jäätteenmäki had specifically and forcefully asked for the information, and that he'd be able to prove it, her coalition parties made it clear that they had no trust in her leadership. She resigned the same evening, citing the lack of political trust, and without admitting any wrongdoing.
Consequently she also resigned as leader of the Center Party on June 25th.
President Halonen has asked Mrs. Jäätteenmäki to continue as the head of a caretaker cabinet[?] until a new cabinet is appointed. However, she did not leave for the crucial summit of EU heads of states on June 19th, which is instead attended by President Halonen, Vice Prime Minister Antti Kalliomäki[?] and Foreign Minister Erkki Tuomioja.
She was succeded by Matti Vanhanen as Prime Minister.