The Constitutional Court (, , ), officially the Constitutional Court of the Kingdom of Thailand, is a Thai court created by the 1997 constitution with jurisdiction over the constitutionality of parliamentary acts, royal decrees, draft legislation, as well as the appointment and removal of public officials and issues regarding political parties. The current court is part of the judicial branch of the Thai national government.

The court, along with the 1997 constitution, was dissolved and replaced by a Constitutional Tribunal in 2006 following the 2006 Thai coup d'état. While the Constitutional Court had 15 members, seven from the judiciary and eight selected by a special panel, the Constitution Tribunal had nine members, all from the judiciary.The Nation, Nine Constitution Tribunal members , 7 October 2006 A similar institution, consisting of nine members, was again established by the 2007 Constitution.

The Constitutional Court has provoked much public debate, both regarding the court's jurisdiction and composition as well as the initial selection of justices. A long-standing issue has been the degree of control exerted by the judiciary over the court.

The decisions of the court are final and not subject to appeal. Its decisions bind every state organ, including the National Assembly, the Council of Ministers, and other courts.

The various iterations of the court have made several significant decisions. These include:

The 1999 decision that Newin Chidchop, the Deputy Minister of Agriculture, could retain his seat in cabinet after being sentenced to imprisonment for defamation. The 2001 acquittal of Thaksin Shinawatra for filing an incomplete statement regarding his assets with the National Anti-Corruption Commission. The 2003 invalidation of Jaruvan Maintaka's appointment as auditor-general. The 2007 dissolution of the Thai Rak Thai political party. The 2014 removal of prime minister Yingluck Shinawatra from office. The dissolution of the Thai Raksa Chart Party before the March 2019 election. The dissolution of the Future Forward Party in 2020 and its successor Move Forward Party in 2024. The removal of Prime Minister Srettha Thavisin in 2024 and his successor Paetongtarn Shinawatra in 2025.

The FY2019 budget of the Constitutional Court is 223.7 million Baht. , its president is Nakharin Mektrairat.

Origins and controversy

Drafting of the 1997 constitution

The creation of the Constitutional Court was the subject of much debate during the 1996–1997 drafting of the 1997 Constitution of Thailand.James R. Klein, "The Battle for Rule of Law in Thailand: The Constitutional Court of Thailand", Senior judges opposed the concept on the grounds that constitutional and judicial review should remain a prerogative of the Supreme Court and that a Constitutional Court would create a fourth branch of government more powerful than the judiciary, legislature, or executive. Judges stated their fear over political interference in the selection and impeachment of judges. The Constitution Drafting Assembly (CDA) eventually made several concessions regarding the composition and powers of the court.

Jurisdiction

The constitution did not give the Constitutional Court the authority to overrule a final judgment of the Supreme Court. An affected party, or a court, could request the opinion from the Constitutional Court if it believed a case involved a constitutional issue. The court where the initial action was pending would stay its proceedings until the Constitutional Court issued its decision. Constitutional court decisions would have no retroactive effect on previous decisions of the regular courts.

The constitution also did not give the Constitutional Court the authority to rule on any case in which the constitution did not specifically delegate an agency the power to adjudicate.

Impeachment

The constitution allowed individual justices to be the subject of impeachment proceedings with the vote of one-fourth of the members of the House or with the approval of 50,000 petitioners. A vote of three-fifths of the Senate is required for impeachment. Earlier drafts had required votes of only 10% of the combined House and Senate to call for a vote of impeachment, and votes of three-fifths of the combined Parliament of Thailand to dismiss a justice.

Appointment

The constitution gave the judiciary a strong influence over the composition of the Constitutional Court. Originally, the court was to have nine justices including six legal experts and three political science experts. A panel of 17 persons would propose 18 names from which parliament would elect the nine justices. The panel president would be the president of the Supreme Court of Thailand, the panel itself would have included four political party representatives. The CDA finally compromised and allowed seven of the justices to be selected by the judiciary, while the remaining eight justices would be selected by the Senate from a list of Supreme Court nominees.

Appointment of the first Constitutional Court

The appointment of the first Constitutional Court following the promulgation of the constitution in 1997 was four month controversy pitting the Senate of Thailand against the Supreme Court. A key issue was the senate's authority to review the backgrounds of judicial nominees and reject nominees deemed inappropriate or unqualified.

Appointment of Amphorn Thongprayoon

After receiving the Supreme Court's list of nominees, the Senate created a committee to review the nominees' credentials and backgrounds. On 24 November 1997, the Senate voted to remove the name of Supreme Court Vice-president Amphorn Thongprayoon, on the grounds that his credentials were dubious and on allegations that he had defaulted on three million Baht in debt. The Supreme Court was furious, arguing the constitution did not empower the senate to do background checks or to reject Supreme Court nominees. The Supreme Court requested a ruling from the Constitutional Tribunal chaired by the House speaker. On 8 January 1998, in a six to three vote, the Tribunal ruled the Senate did not have the authority to do background checks or reject the Supreme Court's nominees. The Tribunal ruled that the Senate's review powers were limited to examining the records of the nominees and electing half of those nominees for appointment.

Immediately after the Supreme Court filed its request to the Tribunal, Justice Amphorn withdrew his name. After the Tribunal's ruling, the Supreme Court elected justice Jumpol na Songkhla on 9 January 1998 to replace Amphorn. The Senate ignored the Tribunal's ruling and proceeded to review Jumphol's background and delayed a vote to accept his nomination for seven days so that the Senate could evaluate Jumphol. Finding no problems, the Senate acknowledged his appointment to the court on 23 January 1998.

Appointment of Ukrit Mongkolnavin

The appointment of former Senate and Parliament president Ukrit Mongkolnavin was especially problematic. The Senate had initially elected Ukrit from the list of ten legal specialists nominated by the selection panel, despite claims by democracy activists that Ukrit was unqualified to guard the constitution because he had served dictators while president of parliament under the 1991–1992 military government of the National Peacekeeping Council.

Stung by the Senate rejection of Amphorn Thongprayoon, the two Bangkok Civil Court judges, Sriampron Salikhup and Pajjapol Sanehasangkhom, petitioned the Constitutional Tribunal to disqualify Ukrit on a legal technicality. They argued that Ukrit only had an honorary professorship at Chulalongkorn University, while the 1997 constitution specifically specifies that a nominee, if not meeting other criteria, must be at least a professor. Echoing the Senate's rejection of Amphorn, the judges also alleged that Ukrit was involved in a multi-million baht lawsuit over a golf course. On 10 January 1998, the Tribunal ruled that the judges were not affected parties and therefore they had no right to request a ruling. Nevertheless, the parliament's president invoked his power as chairman of the tribunal to ask the Senate to reconsider Ukrit's nomination.

On 19 January 1998, the Senate reaffirmed Ukrit's qualifications, noting that his professorship was special only because he was not a government official. Under Chulalongkorn's regulations, he had the academic status of a full professor.

This position inflamed activists and the judiciary, and prompted the parliament president on 21 January to invoke his authority under Article 266 of the 1997 Constitution to order the Constitutional Tribunal to consider the issue. On 8 February, in a four to three vote, the tribunal ruled that Ukrit's special professorship did not qualify him for a seat on the Constitutional Court. The tribunal noted that Chulalongkorn's criteria for honorary professorship were different from its criteria for academic professors, as intended by the Constitution. The Senate ended up electing Komain Patarapirom to replace Ukrit.

Jurisdiction

Under the 2007 Constitution, the court is competent to address the following:

# Matters Sections of the constitution allowing their institution Eligible petitioners Type 1 A petition for a decision as to whether a resolution or regulation of a political party to which the petitioner belongs is contrary to his status and functions as representative, or is contrary to the fundamental principles of the democratic regime of government with the King of Thailand as head of state Section 65, paragraph 3 A member of the political party in question Political party 2 A petition for a decision as to whether any person or political party exercises the constitutional rights and freedoms to undermine the democratic regime of government with the King as head of state, or to acquire the national government power by the means not recognised by the Constitution Section 68 Any person Constitutional defence 3 A petition for a decision as to whether any representative or Senator loses his membership by operation of the Constitution Section 91 At least one-tenth of the existing representatives or senators Membership 4 A petition for a decision as to whether a political party resolution terminating any representative's membership in the party is contrary to his status and functions as representative, or is contrary to the fundamental principles of the democratic regime of government with the King as head of state Section 106 (7) The representative in question Political party 5 A petition for a decision concerning the constitutionality of a draft organic act having been approved by the National Assembly of Thailand Section 141 The National Assembly Constitutionality of draft law 6 A petition for a decision as to whether a draft organic act or act introduced by the council of ministers or representatives bears the principle identical or similar to that which needs to be suppressed Sections 140 and 149 The president of the House of Representatives or Senate Constitutionality of draft law 7 A petition for a decision as to whether a bill having been approved by the National Assembly by virtue of section 150 but having not yet been submitted to the king by the prime minister, or a bill having been reapproved by the National Assembly but having not yet been resubmitted to the King by the prime minister, is unconstitutional, or whether its enactment was in compliance with the requirements of the Constitution Section 154 At least one-tenth of the existing representatives or senators The prime minister Constitutionality of draft law 8 A petition for a decision as to