Thailand's embattled government faces a key court ruling Friday on whether it can go ahead with a fiercely disputed election despite threats by opposition protesters to block the vote.
Prime Minister Yingluck Shinawatra is under intense pressure to step down after nearly three months of street rallies aimed at ousting her elected government and installing an unelected "people's council".
The Constitutional Court was considering a plea from the Election Commission to postpone the February 2 election, a move that could leave the kingdom in protracted political limbo.
The judges have also been asked to rule on whether the power to delay the election lies with the commission or the government, which has insisted that the vote should proceed.
The main opposition party is boycotting the February 2 election, while protesters have vowed to disrupt voting, saying reforms are needed to tackle corruption and vote-buying before polls are held in around a year to 18 months.
But a survey by Bangkok University released on Friday showed that nearly 80 percent of roughly 1,000 respondents planned to vote next month.
On Thursday, protest leader Suthep Thaugsuban threatened to "close every route" to polling stations, saying the election would not be allowed to take place.
Some constituencies have no candidates because demonstrators blocked registrations, so even if Yingluck's party wins it may not have enough MPs to appoint a government.
Nine people have been killed and hundreds injured in grenade attacks, drive-by shootings and street clashes since the latest protests began at the end of October.
Advance voting on Sunday is seen as a litmus test of whether the polls will go smoothly.
The kingdom has been periodically rocked by political bloodshed since her older brother, former prime minister Thaksin Shinawatra, was overthrown by royalist generals in a coup more than seven years ago.
"Red Shirt" supporters of the tycoon-turned politician, who lives overseas to avoid a jail term for corruption, have said they oppose an election delay.
"If there is no election or the election is postponed or a neutral person is appointed prime minister, we will not accept it," Red Shirt chairwoman Thida Thavornseth told reporters.
The Constitutional Court dealt a major setback to the government in November when it ruled that a ruling party bid to make the upper house of parliament fully elected was in breach of the constitution.
Dozens of Yingluck's MPs face a possible five-year ban from politics over that failed bill.
"The status of the Constitutional Court is very controversial," said Sunai Phasuk, a senior researcher with New York-based Human Rights Watch.
"It is a product of a coup in 2006 and acts mainly as a tribunal not a court of justice per se," he said, noting that the government had been "badly crippled" by its rulings.
The demonstrators have staged a self-styled "shutdown" of Bangkok since January 13, erecting roadblocks and rally stages at several main intersections including in the main hotel and shopping districts, although attendance has gradually fallen since last week.
The government on Tuesday declared a 60-day state of emergency in Bangkok and surrounding areas to deal with the unrest.
The decree gives the authorities the power to ban public gatherings of more than five people, prohibit protesters using certain routes and forbid media spreading misinformation.
But the government has not yet used any of those measures, and has ruled out using force to end the rallies.
When a state of emergency was last imposed in 2010 during pro-Thaksin protests, the previous government cracked down with armoured vehicles and soldiers firing live rounds. More than 90 people were killed and nearly 1,900 injured.
The military, traditionally a staunch supporter of the anti-Thaksin establishment, has said it wants to remain neutral during the current standoff, although the army chief has refused to rule out another coup to seize power from Yingluck.
The political dispute comes at a time of disquiet among many Thais about the health of 86-year-old King Bhumibol Adulyadej, and who will be in power to oversee the transition when his more than six-decade reign eventually comes to an end.