Courtesy of Bangkok Pundit
Section 135/1 A person commits an act which is a criminal offence [if they commit one] of the following:
(1) [The person] commits an act of violence, or commits any act which causes harm to [a person's] life, or serious harm to [a person's] body, or the liberty of any person,
(2) [The person] commits an act causing serious damage to a public transportation system, a telecommunications system, or to any infrastructure which has a public benefit, [or]
(3) [The person] commits an act causing damage to the property of any state, or of any person, or to the environment which has caused or is likely to cause significant economic damage.
If such acts are committed with the intention to threaten, or to compel the Thai Government, a foreign government, or an international organisation to do or abstain from doing any act which will cause serious damage or to cause disorder by creating widespread fear among the public [then] that person has committed a terrorist act.
[That person] shall be punished by death, life imprisonment or a term of imprisonment between three years to twenty years, and a fine between 60,000 Baht to 1,000,000 Baht.
Any act of demonstrating, rallying, protesting, opposing or [being part of a] movement to demand the state to assist or to obtain justice, which is an exercise of [a person's] liberty as prescribed in the Constitution, is not a terrorist act.
The law seems pretty clear cut. Of course, we know that the Thai media (The Nation, cough, cough) and the judicial/ criminal justice system in Thailand have already decided that Thaksin is the only one who should follow the law and everybody else--PAD, military-- who commits major crimes against the state and the people should get a free pass.