He was nevertheless arrested at his home in Chelles, Seine-et-Marne on 28 February 1990 on the grounds that he was a threat to public order due to his activities, and he was flown to Senegal on the same day.
[2] In the 6 December 1998 presidential election, Mamboundou ran as the candidate of the High Council of the Resistance (HCR), a coalition of opposition parties.
[11] However, shortly before the election, HCR representative Aloise Obame accused Mamboundou of ordering the purchase of guns in Congo-Brazzaville with the purpose of using them to destabilizing Gabon.
[13][14] He denounced the official results as an "electoral coup d'etat" and called on the people to begin a "graduated response" by engaging in a stay at home ("ghost city") protest.
[18] Prior to the 29 December 2002 local elections, he denounced Bongo, the government, and the ruling Gabonese Democratic Party (PDG) as "a trio for the destruction of Gabon".
[20] Unlike many other opposition leaders, Mamboundou had consistently refused to compromise with Bongo and the PDG, increasing his credibility among many Gabonese.
[21] Prior to the 2005 election, UPG Secretary-General Richard Moulomba claimed that Mamboundou was robbed of victory in 1998 and vowed that it would not happen again.
Marie-Madeleine Mborantsuo, the President of the Constitutional Court, then accused Mamboundou of "public insults against judges" and "clear threats".
[24] Searching for arms, security forces entered the UPG headquarters in Awendjé on 31 March 2006[25] and arrested 15 members of the party.
[33] On 19 July 2009, following President Bongo's death on 8 June, Mamboundou was designated as the candidate of the Alliance for Change and Restoration opposition coalition for the 30 August 2009 presidential election.