A profile of Phumtham Wechayachai, a key leader of the Pheu Thai Party, who survived allegations of using authority to interfere with and dominate the investigation process of the Senate vote-rigging case. The Constitutional Court has ruled that his ministerial status does not end because he retains power and authority.
On 21 January 2026, the Constitutional Court ruled on whether the ministerial status of Mr. Phumtham Wechayachai, former Deputy Prime Minister and Minister of Defense, and Pol. Col. Tawee Sodson, former Minister of Justice, ended individually under the Constitution, Section 170 paragraph one (4) in conjunction with Sections 160 (4) and (5). The case involved all 92 senators, known as the “Blue Senate,” who filed a petition through Mongkol Surasajja, President of the Senate, accusing them of abusing power to interfere with or dominate the investigation of the Senate vote-rigging case by using the Department of Special Investigation (DSI) as a tool to encroach upon the authority of the Election Commission (EC). This was deemed a serious violation of ethics, a breach of the separation of powers principle, and a violation of the rule of law.
Mr. Phumtham Wechayachai, Deputy Prime Minister, was born on 5 December 1953. Nicknamed "Ouan," his original name was "Thawatchai." He completed high school at Tawitthapisek School, earned a Bachelor of Political Science from Chulalongkorn University in 1975, and a Master of Political Science from the same university in 1984. He also completed the National Defence College course at the National Defence College of Thailand in 2004.
Phumtham served as Deputy Director of the Volunteer Project at the Social Research Institute, Chulalongkorn University, starting in 1979. Later, he worked in the private sector at a company and was Assistant Managing Director at the executive office of the Shinawatra Group from 1997 to 1998.
In 2001, he served as Secretary to the Minister of Interior and was an advisor to the Prime Minister (to Assoc. Prof. Dr. Somkid Jatusripitak). He is considered a member of the October generation.
He was also a political officer in the parliamentary service, serving as advisor to the Leader of the Opposition in the House of Representatives (Mr. Sompong Amornwiwatt), former Secretary-General of the Pheu Thai Party, a committee member of the Political Party Development Committee for National Reform according to the Constitution under Election Commission Order 14/2017, former Deputy Minister of Transport in Thaksin Shinawatra’s government, and former Deputy Secretary-General of the Thai Rak Thai Party.
In 2007, he was banned from politics for five years as an executive committee member of the dissolved Thai Rak Thai Party in the 2006 party dissolution case. In 2012, he joined the Pheu Thai Party and was elected Secretary-General at the party meeting on 30 October 2012.
In the 2014 general election, he ran for a party-list seat under the Pheu Thai Party, ranked 21st on the list.
In the 2019 general election, he again ran for a party-list seat under the Pheu Thai Party, ranked 4th on the list, but was not elected because the party had more MPs than constitutionally allowed.
In the 2023 general election, he ran for a party-list seat under the Pheu Thai Party, ranked 100th, but was not elected. Nevertheless, he was considered a key figure in negotiating the formation of the Srettha 1 government and a true key person of the Pheu Thai Party. He even admitted in media interviews that it was the most difficult government formation of his life and is regarded as a direct loyalist to the former Prime Minister Thaksin Shinawatra.
On 22 August, Phumtham was seen at Don Mueang Airport welcoming Thaksin Shinawatra upon his return to Thailand.
After the successful formation of the Srettha 1 government, Phumtham was appointed Deputy Prime Minister and Minister of Commerce. When the Paetongtarn Shinawatra government was formed, he was entrusted to serve as Deputy Prime Minister and Minister of Interior after the Pheu Thai Party regained the Ministry from the Bhumjaithai Party, causing a rift between Pheu Thai and Bhumjaithai.
He was later petitioned for removal by the “Blue Senate” group over allegations of abusing power to interfere in the Senate vote-rigging case.