The suit at the Supreme Court sought to stop Messrs Tinubu and Shettima from being sworn in as president and vice president on 29 May.
The Supreme Court has dismissed the suit filed by the Peoples Democratic Party (PDP) seeking the disqualification of Bola Tinubu as a candidate in the last presidential election.
The suit, which alleged the inappropriate nomination of Mr Tinubu's running mate for the February 20223 presidential election, Kashim Shettima, impliedly sought to stop the president-elect from being sworn in as president on 29 May.
A five-person panel led by Inyang Okoro dismissed the suit unanimously on Friday.
Adamu Jauro, a member of the panel who delivered the lead judgement, held that the PDP lacked the legal right to file a suit on an internal affair of APC.
"It should be noted that no political party can challenge the nomination of another political party.
"A political party lacks the right to challenge the activities of INEC on account of the nomination of another political party's candidate.
"No court has the jurisdiction to entertain such a suit by another party," the court held.
The court said PDP failed to show any harm it suffered because of Mr Shettima's alleged double nomination.
Agreeing with the Court of Appeal's earlier judgement dismissing the suit, Mr Jauro said, "I am in complete agreement with the Appeal Court that the PDP lacks the right to file this suit
"The appellant was unable to point to where the lower court determined the substantive issues on its merit.
"It is clear that the suit is statute-barred. Hence this court has no power to delve into the merit of the merit of the suit."
The judge added: "It is frivolous and bound to fail fraught with manifest malady. It has been a waste of precious time and judicial energy.
"Counsel should do better to advise their clients to desist from suit frivolous matters.
"The appeal is grossly lacking in merit and it is hereby dismissed."
The court awarded the cost of N2 million against PDP and in favour of the respondents
The judgement came three days ahead of the inauguration of Mr Tinubu as Nigeria's president.
Outgoing President Muhammadu Buhari had on Thursday conferred Nigeria's highest national honour, GCFR, on Mr Tinubu preparatory to the president-elect's inauguration on 29 May. The second highest national honour, GCON, was also conferred on Vice President-elect Kashim Shettima.
Background
The PDP's suit predated the February 2023 presidential election. The case differs from the election petition case that the party filed at the presidential election court in the aftermath of the February election to challenge Mr Tinubu's victory.
The party filed the suit challenging the Tinubu/Shettima candidature suit at the Federal High Court in Abuja on 28 July 2022.
Mr Shettima was already the senatorial candidate of the All Progressives Congress (APC) for Borno Central Senatorial District at the time of his nomination as the party's vice-presidential candidate last year.
PDP said he had yet to withdraw his senatorial candidature as of the time his party nominated him as its vice-presidential candidate.
The opposition party argued that such double nominations of a person for elections to different constituencies in an election cycle breached the provisions of sections 29(1), 33, 35 and 84{1) (2)} of the Electoral Act, 2022.
The breach, according to the plaintiff, invalidated the APC's presidential ticket. PDP, therefore, sought an order disqualifying APC and its candidates - Messrs Tinubu and Shettima - from participating in the 2023 presidential election.
But delivering judgement on 13 January, the judge, Inyang Ekwo, dismissed the case on the grounds that PDP lacked the legal right to enquire into what he described as an internal affair of the APC.
Mr Ekwo added that the suit was caught by the principle of estoppel, saying the issue of Mr Shettima's nomination as Mr Tinubu's running mate was earlier decided by another court of competent jurisdiction.
The judge held that the suit was an abuse of the court process and, as such, deserved to be dismissed.
Displeased with the judgement, PDP appealed against it at the Court of Appeal in Abuja.
But the appellate court dismissed the appeal in its verdict on 25 March, exactly one month after the presidential election won by Mr Tinubu and his party were declared to have won.
A three-member panel of Justices of the Court of Appeal affirmed the Federal High Court's decision.
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In the lead judgement delivered by James Abunduga, the appellate court described the PDP as a meddlesome interloper for dabbling into the affairs of the APC.
The PDP further appealed to the Supreme Court.
A five-person panel of the court led by Inyang Okoro heard the appeal on Monday and fixed it today (Friday) for judgement.
At the hearing, the PDP, through its lawyer, Joe Agi, a Senior Advocate of Nigeria, urged Supreme Court to set aside the judgement of the Court of Appeal on the matter and grant his client's prayer for cancellation of
Counsel for Tinubu and the APC, Babatunde Ogala, SAN, sought the dismissal of the suit on the premise that it was bereft of any merit.
Besides, the respondents contended that the matter had become status barred in view of the expiration of the period allowed for the hearing and determination of such a pre-election case.
On its part, INEC, through its lawyer, Adebiyi Adetosoye, said it supported Mr Tinubu and APC's demand for the appeal to be dismissed with substantial cost.
