I've heard different numbers quoted, some said we had 17 coups since Thailand became a constitutional democracy, some said 20, so I decided to look it up and see if I can tell this story properly, just to help overcome the short memory syndrome we seem to have as a nation. I"m probably the worst one of all with a short memory syndrome, : )
Luckily the orality of the internet makes up for that.
Anyway, one of the books I've been digging into is Likhit Dhiravegin's Thai Politics: Selected Aspects of Development and Change.
According to this book, only between 1938-1947 and between 1951-1957 was the country spared from either a successful coup or an unsuccessful coup, which was termed a rebellion.
Between 1938-1947, there was the intervention of World War II. The Japanese forces which marched through Thailand plus the strong rule of Field Marshall Pibulsongkram (1951-1957) brought about political stability.
In Thai political culture, it seems that "a strongman is almost synonymous with political stability". How sad.
What shocked me was not the number of coups we had (which seems to be about 13, someone please help me count exactly how many there were...). Well, it was the number of years the Thai nation was led by dictators (I think some older generataion might argue that there was one or two benevolent ones there.)
The total years of non-elected military appointed Prime Ministers since 1932 was 33 years. In 64 years, we've had 33 years of non-democratic rule.
Two periods of dictators seems to stand out markedly, that of Field Marshall P. Phibulsongkram, who had two terms of non-elected rule, nearly 16 years in total.
I remember my mother telling me a few stories about how he organized society back then. Two stood out, there was one about the ancient trees on Wireless Road that were razed down because his son was killed when his car rammed into one tree. The other story was about how he imposed a dress code so that the people can look modern.
Then there was the period of the most hated dictators: Sarit-Thanom who killed thousands of students between 1973-1976 in Sanam Luang. I was very young and living abroad at that time. I remember my dad calling me to the TV to watch the news about Thailand. The terrible feelings of sadness of that moment was burnt into my memory. When we eventually came back to Thailand, my friends and family had stories to tell about friends and family who died or whose lives were marked during that time. My parents came from Sakolnakorn, what was marked then the red area, "Communist" stronghold and hideout of those students that fled into the forest. My mom to this day is full of stories how good people sincerely wanting to improve the social conditions were labeled by people who were threatened by their vision and prosecuted as communists. I have a strong suspicion that what goes on in the South now is not much different.
Anyway, excuse me for my rambling. But here's the list of PM and coups put together.
PM Phraya Manopakorn Nitithada (Mano) period: June 1932-June 1933, tenure- 1 yr
Coup no. 1: June 20, 1933 (Khana Ratpraharn - coup)
PM Col. Phraya Paholpolpayuhasena (Pahol) Military, June 1933- Dec.1938, tenure: 5 yrs, 5 mths, 23 days
Coup no. 2: October 11, 1933 (Kabot Boworadej - rebellion)
Coup no. 3: August 3, 1935 (Kabot Naisip- rebellion)
Coup no. 4: January 29. 1938 (Kabot Praya Songsuradej- rebellion)
PM Field Marshall P. Pibulsongkram, Military, Dec. 1938-Jul 1944, tenure: 5 yrs, 11 mths, 11 days
PM Khuang Aphaiwong, Civillian, Aug 1944-Aug 1945, tenure: 1 yr, 6 mnths, 17 days
PM Tawee Boonyaket Civilian, Aug 1945-Sep 1945 , tenure: 17 days
PM M.R. Seni Pramoj , Civilian, Sep 1945-Jan1946, tenure: 10 mths, 13 days
PM Khuang Aphaiwong, Civilian, Jan. 1946-Mar.1946, tenure: 3 months
PM Pridi Panomyong, Civilian, March 1946-Aug 1946, tenure: 4 mths, 17 days
PM R. Admiral Tawan Thamrongnavasawat, Military, Aug 1946-Nov 1947, tenure: 1 yr, 2 mths, 18 days
Coup No. 5: November 8, 1947 (Khana Ratprahar-coup)
PM Kuang Aphaiwong, Civilian, Nov. 1947-April1948, tenure 6 months
Coup No. 6: October 1, 1948 (Kabot Senathikarn-rebellion)
PM Field Marshall P. Phibulsongkram (Pibul), Military, April, 1948-Sep. 1957, tenure: 9 1/2 years
Coup No. 7: February 26, 1949 (Kabot Wangluang-rebellion)
Coup No. 8: June 29. 1951 (Kabot Manhatton-rebellion)
Coup No. 9: November 29, 1951 (Khana Ratpraharn-coup)
Coup No. 10: September 16, 1957 (Khana Ratpraharn-coup)
PM Pote Sarasin, civilian, Sep 1957-Jan. 1958, tenure: 4 months
PM Gen. Thanom Kittikachorn Jan 1958-Oct 1958, tenure: 9 months
PM Field Marshal Sarit Thanarat Feb 1959-Dec 1963, tenure: 4 3/4 years
PM Field Marshal Thanom Kittikachorn, Dec 1963-Feb1969, tenure: 6 1/6 years, and Feb. 1969-Nov 1971, 2 3/4 years, and Nov. 1971-Oct.1973, 2 years
Dictators were brought down by student uprising. Wikipedia article on "The 1973 democracy movement"
PM Sanya Dharmasakti, (14 October 1973 - 26 February 1975)
PM Seni Pramoj, (26 February - 14 March 1975) (2nd time)
PM Kukrit Pramoj, (14 March 1975 - 20 April 1976)
PM Seni Pramoj, (20 April - 6 October 1976) (3rd time)
PM Tanin Kraivixien, installed by the military (8 October 1976 - 20 October 1977)
Coup No. 11: October, 1977.
PM General Kriangsak Chomanan, appointed (12 November 1977 - 3 March 1980)
PM General Prem Tinsulanonda, appointed (3 March 1980 - 4 August 1988)
PM General Chatichai Choonhavan, elected (4 August 1988 - 23 February 1991)
Coup No. 12: February, 1991.
PM Anand Panyarachun, appointed, civilian (7 March 1991 - 7 April 1992) (1st time)
PM General Suchinda Kraprayoon, military, (7 April - 24 May 1992)
PM Meechai Ruchuphan, 24 May 1992 - 10 June 1992 (acting)
PM Anand Panyarachun, appointed(10 June - 23 September 1992) (2nd time)
PM Chuan Leekpai, elected (23 September 1992 - 13 July 1995) (1st time)
PM Banharn Silpa-Archa, elected, (13 July 1995 - 1 December 1996)
PM General Chavalit Yongchaiyudh, elected (1 December 1996 - 9 November 1997)
PM Chuan Leekpai, elected, (9 November 1997 - 9 February 2001) (2nd time)
PM Thaksin Shinawatra, elected. (9 February 2001 - 19 September 2006)
Acting PM Chitchai Wannasathit, 5 April - 23 May 2006 (acting for Thaksin)
Coup No. 13: September, 2006