In June 2005 Sallah was, along with the other three opposition MPs, expelled from the National Assembly on the grounds of dual party membership. NADD had been registered as a political party and the Supreme Court of The Gambia judged that it went against the Gambian Constitution to belong to two parties at the same time. Critics claimed that the move was nothing but an attempt to silence the parliamentary opposition, as there was nothing in the Constitution regulating political alliances. On 29 September a by-election was held, in which Sallah was reelected with a huge margin.
On 15 November 2005, Sallah was arrested along with two other opposition leaders on the grounds of subversion, accused of having collaborated with the President of Senegal.