Impeachment as Constitutional Accountability and Political Instrumentalization: A Comparative Systematic Literature Review

Impeachment is a hybrid constitutional mechanism at the intersection of law and politics, designed to enforce accountability yet susceptible to strategic political deployment. This duality appears in recent cases. In the Philippines, Sara Duterte was impeached by the House in 2025 on charges of fund misuse and betrayal of public trust, only for the Supreme Court to nullify the proceedings on a procedural technicality. In the United States, Donald Trump became history's only twice-impeached president, acquitted both times along strict party lines. In France, former President Nicolas Sarkozy was convicted of corruption by the Court of Cassation in 2024 through a judicial, not legislative, process. In Italy, former Prime Minister Silvio Berlusconi survived decades of legal proceedings through coalition-protected maneuvering. Despite growing scholarship, literature remains fragmented across legal, political, and comparative domains. Guided by PRISMA-informed identification and screening procedures, conducted as a single-reviewer systematic literature review across six databases (Scopus, Web of Science Core Collection, HeinOnline, JSTOR, ProQuest Central, and Google Scholar) covering publications from 1913 to 2025, this review examined impeachment as both a mechanism of constitutional accountability and a form of political instrumentalization across the Philippines, the United States, France, and Italy. Following PRISMA-guided screening of 921 records, 159 studies were included in the final synthesis. Synthesis organized findings into five categories: (1) conceptual foundations of impeachment, (2) institutional and legal design conditions, (3) political and strategic dynamics, (4) comparative country patterns, and (5) democratic and constitutional implications. Findings reveal impeachment is a vital but fragile institution whose effectiveness depends on procedural safeguards, evidentiary seriousness, institutional independence, and democratic norms. Under partisan polarization, coalition instability, and procedural vulnerability, impeachment is frequently instrumentalized, undermining its legitimacy. Strengthening safeguards and institutional independence, and mitigating partisanship, are essential to preserving impeachment's constitutional role.