By Ulf Laessing
TRIPOLI, Feb 20 (Reuters) - Libyans head to the polls on Thursday to elect a body to draft a new constitution, marking a step in the country's transition after the overthrow of dictator Muammar Gaddafi in 2011.
Western powers hope a peaceful vote will help move the North African country a bit closer towards democracy but it comes at a time of heightened political tensions.
The government of Prime Minister Ali Zeidan is struggling to assert authority and rein in militias who helped topple Gaddafi but kept their weapons to become political players.
Two of the most powerful militias threatened on Tuesday to dissolve the General National Congress (GNC) assembly which they accuse like many ordinary Libyans of paralyzing the country by endless infighting.
On Wednesday the militiamen removed forces they had brought into central Tripoli in a show of force after the United Nations called for restraint, but the incident is a reminder of the country's political fragility.
Libya desperately needs a viable government and system of rule so that it can focus on reconstruction and on healing the divisions opened up by the 2011 war that toppled Gaddafi.
Many normal Libyans are tired of militias and have little trust in political institutions after four decades of quirky one man-rule.
Voter registration was sluggish. More than one million people signed up but this is well below the almost the three million registered for the parliamentary elections in 2012.
The 60 members of the constitutional committee will have 120 days to draft the charter. They will be divided equally between Libya's three regions: Tripolitania in the west, Cyrenaica in the east, and Fezzan in the south.
The model resembles the committee that drafted Libya's pre-Gaddafi constitution, implemented when it became an independent state in 1951.
Those who will draft the constitution will need to take into account political and tribal rivalries and calls for more autonomy in the east when deciding what political system Libya will adopt. Their draft will be put to a referendum.
In the east, armed protesters have seized major oil ports since summer to demand a greater share of energy wealth and political autonomy, draining up vital oil exports.
The group occupying the eastern oil ports has dismissed the vote as fake.
The election is also boycotted by the Amazigh, or Berber, a minority which lives in the west in close proximity to oil installations.
Its leader Ibrahim Makhlouf has rejected the vote because the Amazigh wanted a bigger say in the body and guarantees that their language will become one of the official languages.
In the past, to demand their rights, Amazigh have blocked oil installations such as the Mellitah oil and gas complex, co-owned by Italy's ENI, as well as pipelines.
Attempts to write a new constitution have been repeatedly delayed because of political infighting within the GNC, which was elected for an 18-month term last July in Libya's first free election in nearly 50 years.
The GNC agreed this week to hold new elections this year after its plan to extend its mandate beyond the original date of Feb 7 had sparked an outcry.
Gaddafi ostensibly ruled Libya by a bizarre set of laws drawn up by him in his Green Book, although in practice he and his family ran a totalitarian state where no coherent political opposition was tolerated and rival tribes were bought off or played off against each other.