By Amy Sawitta Lefevre
BANGKOK, April 21 (Reuters) - A Thai court will decide this week whether to give embattled Prime Minister Yingluck Shinawatra more time to defend herself against charges of abuse of power, accusations that could bring her down, or whether to move swiftly to a verdict.
The fate of Yingluck and her government will determine the course of politics in Thailand which is polarised between the supporters of her and her brother, ousted former premier Thaksin Shinawatra, and supporters of the royalist establishment.
The confrontation between the two sides, marked by occasional violence, has undermined growth in Southeast Asia's second biggest economy.
Yingluck's government has faced months of sometimes violent anti-government protests but it appeared to be weathering the storm until legal challenges against her began to mount in February.
The charges Yingluck faces this week relate to the transfer of National Security Council chief Thawil Pliensri in 2011, which opponents say was done to benefit her party. The Constitutional Court will decide on Wednesday whether to grant her an extension to prepare her defence.
If the court eventually finds her guilty, Yingluck will be forced to step down.
"If the court does not grant the prime minister an extension this week and there is enough evidence, then the next court date will be the verdict," Constitutional Court spokesman Pimon Thampitakphong told Reuters on Monday, adding that the verdict could come at the end of April.
The prime minister has also been charged with dereliction of duty for overseeing a state rice-buying scheme critics say was riddled with corruption. The National Anti-Corruption Commission, which brought the charges against her, rejected a request by her lawyers last week to allow two more witnesses.
The commission is expected to deliver its ruling in May. If found guilty, Yingluck could be removed from office and may get a five-year ban from politics.
Thailand has been in conflict since 2006 when then premier Thaksin was ousted by the army. The former telecoms tycoon turned populist politician lives in self-imposed exile but is hugely popular in the north and northeast.
The crisis broadly pits the Bangkok-based middle class and conservative establishment, who see Thaksin as a corrupt crony capitalist and threat to their interests, against the mostly poorer supporters of Yingluck and Thaksin.
Long-simmering tension erupted last November when the lower house of parliament passed an amnesty bill that critics said was designed to let Thaksin come home without facing jail time for a corruption conviction he said was politically motivated.
That bill was eventually rejected by the Senate but the street movement against it spiralled into a full-blown attempt to remove Yingluck.
The protesters disrupted a snap election she called for Feb. 2, which was nullified by a court in March.
Last week Somchai Srisuthiyakorn, an election commissioner, said a new election could be held at the earliest in July.
The protesters, determined to rid the country of Thaksin's influence, want Yingluck to resign to make way for broad political and electoral reforms before a new election is held.
Adding to the instability, "red shirt" supporters of the Shinawatras say they will resist attempts to force Yingluck from office.
"A day before the Constitutional Court hands down its verdict, we will hold a massive rally near Bangkok to support Yingluck," said Thanawut Wichaidit, a spokesman for the pro-government United Front for Democracy Against Dictatorship.
"Thailand is heading toward a dark and dangerous chapter so we must fight back, but with our voices only and not with weapons." (Additional reporting by Panarat Thepgumpanat; Editing by Alan Raybould and Robert Birsel)