President Corazon Aquino signed Republic Act No. 7160, the Local Government Code of 1991, on October 10, 1991. This landmark legislation operationalized the constitutional mandate for local autonomy under the 1987 Constitution. It took effect on January 1, 1992.

The Local Government Code took full effect on January 1, 1992, triggering the massive devolution of powers, functions, and personnel from national agencies to LGUs. The transition required reorganization of both national and local bureaucracies.

The Supreme Court upheld the power of the President to discipline local officials through administrative proceedings under the LGC. The ruling affirmed Section 60 of RA 7160, granting the President supervisory authority over local governments.

The Supreme Court ruled on the proper application of preventive suspension under Section 63 of the LGC. The Court held that preventive suspension is mandatory when evidence of guilt is strong and the charge involves dishonesty, oppression, grave misconduct, or neglect in office.

The Supreme Court declared that the Internal Revenue Allotment (IRA) is an automatic release mandated by the Constitution and the LGC, not subject to annual budget appropriation. LGUs have a constitutional right to their just share in national taxes.

The Supreme Court clarified that an elective local official's three-consecutive-term limit under Section 8, Article X of the Constitution and Section 43(b) of the LGC applies to the same position. Involuntary interruption breaks the continuity and allows a fourth term.

The Supreme Court interpreted Section 44 of the LGC on the rules of succession when an elective local official is permanently removed from office. The Vice-Mayor or Vice-Governor assumes the vacated office for the unexpired term.

The Supreme Court struck down a Manila ordinance that abolished certain elected barangay positions, ruling that it violated the constitutional guarantee of barangay autonomy. The LGC protects the composition and structure of barangays from local executive interference.

The Supreme Court recognized the standing of LGUs to challenge national government acts that impair their fiscal autonomy. This case reinforced LGU rights to legal remedies when the national government infringes on powers devolved under the LGC.

The Supreme Court ruled that the 40% share of LGUs in national internal revenue taxes under Section 284 of the LGC should be computed based on all national internal revenue taxes, not just those collected by the Bureau of Internal Revenue. The ruling was promulgated in April 2018 and reaffirmed in July 2018.

The Department of Budget and Management and the Department of the Interior and Local Government issued joint guidelines to prepare for the full implementation of the Mandanas ruling. The guidelines addressed the transition to the expanded IRA base.

President Duterte signed Executive Order No. 138 operationalizing full devolution of powers and functions to LGUs in accordance with the Mandanas ruling. The order transferred additional functions from national agencies to LGUs starting January 2022.

The 2022 national budget fully implemented the Mandanas ruling, with LGUs receiving significantly increased IRA based on all national internal revenue collections. The IRA share nearly doubled for most LGUs, fundamentally altering local fiscal capacity.