Oct. 4, 2025, 2:01 AM EDT / Updated Oct. 4, 2025, 2:06 AM EDTBy Arata Yamamoto and Jennifer JettTOKYO — Japan’s governing party elected Sanae Takaichi as its new leader on Saturday, setting her up to become the U.S. ally’s first female prime minister.Takaichi defeated Shinjiro Koizumi 185 to 156 in a second-round runoff vote to become leader of the conservative Liberal Democratic Party (LDP), which has governed Japan almost uninterrupted since the end of World War II.The leadership race was triggered last month when Prime Minister Shigeru Ishiba said he would step down after a year in office. Though Takaichi is likely to succeed him as prime minister of Japan, the world’s fourth-largest economy, when parliament votes later this month, it is not guaranteed since the LDP-led coalition lost its majority in both houses in the past year. Takaichi, 64, a conservative nationalist who lists former British leader Margaret Thatcher as one of her role models, was an ally of assassinated former Prime Minister Shinzo Abe, Japan’s longest-serving leader.But there are concerns that Takaichi’s nationalistic historical views could cause friction with China, Japan’s top trading partner.Koizumi, 44, the son of former Prime Minister Junichiro Koizumi, would have been Japan’s youngest leader since Hirobumi Ito, who was just a few months younger than Koizumi when he became the country’s first prime minister in 1885.The party voted on five candidates in the first round, with Takaichi securing 183 votes to Koizumi’s 164. Yoshimasa Hayashi, 64, the top spokesperson for the current Japanese government, came third with 134 votes after a recent surge in polls.Votes in the first round were divided evenly between 294 LDP lawmakers and almost 1 million rank-and-file party members who were represented by 295 votes. Lawmakers favored the more moderate Koizumi, while party members preferred Takaichi, who has a passionate hard-line base. In the second round, lawmakers had the same number of votes while rank-and-file party members had 47, representing the 47 prefectures of Japan.Lawmakers in the second round voted 149 to 145 in favor of Takaichi, while party members gave her 36 votes compared with Koizumi’s 11.Arata Yamamoto reported from Tokyo, and Jennifer Jett from Hong Kong.Arata YamamotoArata Yamamoto has been an NBC News producer in Tokyo since 1993.Jennifer JettJennifer Jett is the Asia Digital Editor for NBC News, based in Hong Kong.