In 1989, he led the legal defence team for Lt. Gen Christon Tembo, who was accused by the Kenneth Kaunda government of conspiracy to overthrow the government, which was judged as an act of treason worthy of the death penalty; Tembo won the case against the state, and Mwanawasa’s fame among the anti-Kaunda opposition grew. After Frederick Chiluba was elected as President, he appointed Mwanawasa as Vice-President in November 1991. Mwanawasa left his firm in March 1992.
Mwanawasa served as Vice-President until he resigned in July 1994. In 1996 he unsuccessfully contested Chiluba for the presidency of the Movement for Multiparty Democracy. After the loss, Mwanawasa retired from politics until the 2001 election.
In August 2001, the National Executive Committee of MMD elected Mwanawasa as its presidential candidate for the 2001 election. He won the election, held on 27 December 2001, with 29% due to Zambia’s first past the post system, beating 10 other candidates including two other former vice-presidents (Godfrey Miyanda and Gen. Christon Tembo); Anderson Mazoka came in a close second with 27%, according to official results. Mwanawasa took office on 2 January 2002. However, the results of the elections were disputed by main opposition parties, including Mazoka’s United Party for National Development, which many observers claim had actually won the elections. Both domestic and international election monitors cited serious irregularities with the campaign and election, including vote rigging, flawed voter registration, unequal and biased media coverage, and the MMD’s improper use of state resources. In January 2002, three opposition candidates petitioned the Supreme Court to overturn Mwanawasa’s victory. While the court agreed that the poll was flawed, it ruled in February 2005 that the irregularities did not affect the results and declined the petition.