provincial legislature of Santa Cruz in 1989. The Justicialist Party (PJ), led by Carlos Menem, returned to the presidency in the 1989 general elections. She served as interim governor of Santa Cruz for a couple of days, after the impeachment of Ricardo del Val in 1990. She organized Néstor's political campaign when he was elected governor of Santa Cruz in 1991. In 1994, she was elected to the constituent assembly that amended the Constitution of Argentina. She was elected national senator in the 1995 general elections. She opposed some bills proposed by Menem, such as a treaty with Chilean president Patricio Aylwin that benefited Chile in a dispute over the Argentina–Chile border. The Minister of Defense Oscar Camilión was questioned in Congress about the Argentine arms trafficking scandal; Kirchner told him that he had to resign, which he refused to do. As a result, she made a name for herself as a troublemaker. She was removed from the PJ bloc in the Congress in 1997 for misconduct. She resigned her senatorial seat that year and ran for national deputy in the 1997 midterm elections instead. Menem ended his term of office in 1999 and was replaced by Fernando de la Rúa. Fernández de Kirchner took part in a commission to investigate money laundering with fellow legislator Elisa Carrió, and got into conflicts with her. She ran again for senator in the 2001 midterm elections. Néstor Kirchner was elected president in 2003, and she became the First Lady. Under these circumstances, she sought a lower profile in Congress. Her husband had a political dispute with the previous president, Eduardo Duhalde. Their dispute continued during the 2005 midterm elections. Without consensus in the PJ for a single candidate for senator of the Buenos Aires province, both leaders had their respective wives run for the office: Hilda González de Duhalde for the PJ, and Cristina Fernández de Kirchner for the Front for Victory. She won the election. Presidential campaigns 2007 presidential campaign The presidential election was held on 28 October 2007. With Fernández de Kirchner leading all the pre-election polls by a wide margin, her challengers focused on forcing her into a ballotage. To win in a single round, a presidential candidate in Argentina needs either more than 45% of the vote, or 40% of the vote and a lead of more than 10 percentage points over the runner-up. However, with 13 challengers