<P> In April 1990 mid-level officers attempted unsuccessfully to overthrow the government and 69 accused plotters were executed after secret trials before military tribunals . In December 1990 the first stage of partisan elections was held at the local government level . Despite low turnout there was no violence and both parties demonstrated strength in all regions of the country, with the SDP winning control of a majority of local government councils . </P> <P> In December 1991 state legislative elections were held and Babangida decreed that previously banned politicians could contest in primaries scheduled for August . These were canceled due to fraud and subsequent primaries scheduled for September also were canceled . All announced candidates were disqualified from standing for president once a new election format was selected . The presidential election was finally held on 12 June 1993, with the inauguration of the new president scheduled to take place 27 August 1993, the eighth anniversary of President Babangida's coming to power . </P> <P> In the historic 12 June 1993 presidential elections, which most observers deemed to be Nigeria's fairest, early returns indicated that wealthy Yoruba businessman M.K.O. Abiola won a decisive victory . However, on 23 June, Babangida, using several pending lawsuits as a pretense, annulled the election, throwing Nigeria into turmoil . More than 100 were killed in riots before Babangida agreed to hand power to an interim government on 27 August 1993 . He later attempted to renege this decision, but without popular and military support, he was forced to hand over to Ernest Shonekan, a prominent nonpartisan businessman . Shonekan was to rule until elections scheduled for February 1994 . Although he had led Babangida's Transitional Council since 1993, Shonekan was unable to reverse Nigeria's economic problems or to defuse lingering political tension . </P> <P> With the country sliding into chaos Defense Minister Sani Abacha assumed power and forced Shonekan's resignation on 17 November 1993 . Abacha dissolved all democratic institutions and replaced elected governors with military officers . Although promising restoration of civilian rule he refused to announce a transitional timetable until 1995 . Following the annulment of the June 12 election the United States and others imposed sanctions on Nigeria including travel restrictions on government officials and suspension of arms sales and military assistance . Additional sanctions were imposed as a result of Nigeria's failure to gain full certification for its counter-narcotics efforts . </P>

The evolution of nigeria as a political unit