Thailand votes on Sunday for a new constitution that aims to subdue political parties and give the generals a permanent role in overseeing the country's economic development, senior military officers say.

The kingdom of Thailand has a long history of coups. But interviews with officers, including two generals, show the military's ambition is to make such interventions unnecessary by weakening political parties and maintaining permanent influence over elected governments.

Future governments, they said, would be legally obliged to follow a 20-year national development plan set by the army.