REPUBLIC of the PHILIPPINES, represented by SOLICITOR GENERAL JOSE C. CALIDA v. MARIA LOURDES P.A. SERENO, G.R. No. 237428, May 11, 2018 [J. Tijam, En Banc] DOCTRINE OF THE CASE: Quo warranto as a remedy to oust an ineligible public official may be availed of when the subject act or omission was committed prior to