… an election cannot be invalidated by reason of non-compliance with the provisions of the Act if it appears to the Election Tribunal or court that the election was conducted substantially in accordance with the principles of the Act and that the non-compliance did not affect substantially the result of the election. In other words, a petitioner cannot be heard to say that an election is invalid by reason of non-compliance with the principles of the Act if it appears to the Election Tribunal or Court that the election was conducted substantially in accordance with the principles of the Act and that the non-compliance did not affect substantially the result of the election. The words “cannot be heard to say” above are trite legalism that express the notion of estoppel, as a respondent can say in defence, the petitioner cannot be heard to say that the election is invalid.
— Niki Tobi, JSC. Buhari v. INEC (2008) – SC 51/2008