In November, the national assembly transmitted the bill to the president for his assent.
Compulsory direct primaries for political parties and electronic transmission of election results are among the amendments proposed by the national assembly.
The president said the amendment may open up the electoral system to a plethora of litigations based on diverse grounds and issues of law, adding that adopting direct primary violates spirit of democracy.
“The amendment as proposed is the violation of the underlying spirit of democracy, which is characterised by freedom of choices of which political party membership is a voluntary exercise of the constitutional right of freedom of association,” Buhari said in the letter.
“The proposed amendment might also give rise to a plethora of litigations based on diverse grounds and issues of law, including but not limited to the fact that the proposed amendment could not work in retrospect, given that the existing constitution of the parties already registered with the Independent National Electoral Commission (INEC) permits direct, indirect and consensus primaries.
“I hereby signify to the national assembly that I am constrained to withhold assent to the bill in line with section 58 (1) of the 1999 constitution.”
The president said his decision to decline assent to the bill was informed by counsel from the relevant ministries, departments and agencies (MDA).
The letter was also read on the floor of the house of representatives by Femi Gbajabiamila, the speaker.