BANGKOK, April 6 (Reuters) - Thailand's King Maha Vajiralongkorn signed a new constitution at a glittering palace ceremony on Thursday, an essential step towards holding an election that the military government has promised to restore democracy after a 2014 coup. The constitution is Thailand's 20th since the end of absolute monarchy in 1932 and critics say it will still give the generals a powerful say over Thai politics for years, if not decades. The latest changes, made public for the first time when the constitution was published in the Royal Gazette to become law, also underlined the king's power in the event of a crisis, analysts said. "May the Thai people be united in following and protecting the constitution to maintain democracy and their sovereignty," an officer with the Royal Scribes Bureau said at the ceremony, on behalf of the king. The long-awaited constitution replaces an interim document put in place after the 2014 coup. Thais approved the outline of the new constitution in a referendum last August but the palace requested changes in January after King Vajiralongkorn took over from his revered late father, King Bhumibol Adulyadej, who had ruled for more than seven decades. One change allows the king to travel abroad without appointing a regent. The king has spent much of the past few years in Germany, where he has a son in school. Another change was the removal of a clause giving power to the constitutional court and other institutions in the event of an unforeseen crisis. Removing it underlined the king's role. "In practice, the king will have more say, more power," Kan Yuenyong, executive director of think-tank Siam Intelligence Unit, told Reuters. There are still many steps before a general election can be held, or even until a ban is lifted on party politics. According to the timeline set out in the constitution, it could be late 2018 before a ballot and unforeseen delays are still possible. The army initially promised an election in 2015, after seizing power, in the name of ending political turmoil, from a government run by Yingluck Shinawatra, sister of Thaksin Shinawatra, a populist leader ousted in 2006. Thailand's main political division remains between a Bangkok-based strongly royalist and pro-army elite and poorer supporters of the Shinawatras' movement, particularly from the rural north and northeast. Yingluck's Pheu Thai Party said it was more optimistic about election prospects. "With the constitution in place, an election seems more a reality," Chavalit Vichayasuthi, its acting deputy secretary-general, told Reuters. The government should lift a ban on political activities so parties can campaign, said Abhisit Vejjajiva, a former prime minister and leader of Thailand's other key political party, the Democrat Party. "We are ready for the election," he said. "We still aren't allowed to hold meetings, but we're doing what we can." One of the most controversial provisions of the new constitution is for the outgoing military government to appoint a senate that will have a say in appointing the prime minister. The junta has argued the measure is necessary to prevent coups in a transition period after the election. Thailand has had 12 successful coups in the past 85 years. Thursday is a public holiday to mark the establishment of the Chakri dynasty 235 years ago. The current king, himself a former soldier, is also known as King Rama X in the dynasty.