It is enshrined in Islam as a tenent to lie to enemies and to break truces and agreements. Not just the so called palestinians, but all Muslims will always break any 'agreement' they make with an Infidel. Agreements with Infidels are never considered to be valid at all anyway under Islamic Law.
Only fools and liberals expect a Muslim to keep an agreement. In Islam, negotiations are only a delaying tactic to build up forces, weapons, and ammunition. They are never meant to be real.
The only way to form a truce with a Muslim nation is to crush them to the point that they can no longer fight. Because if they have the ability to wage war of any kind, they always will in every case. Regardless of any promises or documents they sign, which they consider to be invalid anyway.
