In 2005, Sophon accused the United States of being the mastermind behind bombings in the South Thailand insurgency. As a Senator, Sophon accused Prime Minister Thaksin Shinawatra of taking part in the Finland Plan and using gains from the privatization of state energy company PTT in a plan to overthrow the Chakri dynasty and establish a communist dictatorship. It was revealed in April 2007 that Sophon was paid by the military junta to criticize deposed Premier Thaksin Shinawatra following the 2006 Thailand coup. However, Sophon continued to deny that he received any payment.
- The Nation, Pipeline Panel Makes Little Headway, 28 January 1998
- (in Thai) Matichon, ส.ส.ปชป.เชื่อ”ต่างชาติ”มีส่วนแทรกแซง, 7 April 2005
- The Bangkok Post, "TRT goes on offensive over 'Finland Plan'", 22 May 2006
- The Nation, Saprang's cousin given PR work 'because of experience', 11 April 2007