The sister of Thailand’s king entered the race to become prime minister on Friday as the candidate of a populist party. The move is an unprecedented foray into politics by a royal that instantly upended the first election since a 2014 military coup, Reuters said. Princess Ubolratana Rajakanya Sirivadhana Barnavadi, 67, the elder sister of King Maha Vajiralongkorn, was nominated by a party loyal to ousted premier Thaksin Shinawatra, the figure at the center of political turbulence. The leader of a pro-military party in Thailand said on Friday its rival’s nomination of the king’s elder sister as its prime ministerial candidate may breach election law.