South Korea’s ruling party candidate for next year’s presidential election on Wednesday said he was not in favour of Japan joining the US and South Korea in a three-way military alliance, questioning whether Tokyo was a “trustworthy friend”. Lee Jae-myung, of the Democratic Party, also said he was opposed to any additional deployment of the highly-sophisticated US missile defence system known as the Terminal High Altitude Area Defence (THAAD), seen by China as a direct security threat. “Needless to say, I am opposed to a three-way military alliance including Japan,” Lee told journalists. Seoul to develop own ship-based gun to replace Dutch, US naval interception systems “Is Japan a friendly country which is always trustworthy?” he asked, noting Japan was persistent in laying territorial claims to a cluster of islets controlled by South Korea but claimed by Japan. It is known as Dokdo by Seoul and Takeshima by Tokyo. “South Korea-US-Japan military alliance would be a very dangerous thing” as long as Japan continues raising issues with Dokdo and taking “ambiguous attitude” toward its past wrongs, Lee said. The politician said he did not “totally” agree that THAAD in South Korea would be helpful for the country’s national interests and stability in the region and for that reason, he had opposed “in principle” its deployment in the South. “Once deployed, however, my position is that there shouldn’t be any additional deployment of THAAD,” he said. Lee’s remarks suggest if he wins the March election, he will continue with the outgoing liberal president Moon Jae-in’s policy of opposing further deployment of THAAD, which was introduced in 2016 under Moon’s conservative predecessor Park Geun-hye, now in jail for corruption. Polls suggest Lee is running behind Yoon Suk-yeol, a former prosecutor who has been nominated as the candidate for the conservative opposition People Power Party. China hit South Korea with trade sanctions and restrictions on K-dramas, films and concerts in retaliation against THAAD. Will Japan’s new China-friendly foreign minister help to thaw ties? Yoon earlier sparked a diplomatic row in July when he said China “should get rid of its own long-range radar along its borders” before calling for the withdrawal of the THAAD system from South Korea. He added that South Korea’s security and diplomatic interests were aligned closely with those of the US, stating that Seoul’s foreign relations “should be founded on a strong Korea-US alliance”. Chinese ambassador to South Korea Xing Haiming countered that view, saying the US placing THAAD in the South had “seriously undermined” China’s security interests, and denying that the Chinese radar poses threats to the South. “China-Korea relations are by no means an accessory to Korea-US relations,” Xing wrote in a statement. “China respects Korea’s foreign policies. But it is our stance that Korea-US relations should not hurt the interests of China”. Park Won-gon, a political-science professor at Ewha Womans University, said a three-way military alliance had not been mooted by any Japan, South Korea or the US. “It is unrealistic to pursue such a military alliance as Washington knows too well the South Korea-Japan tensions stemming from historical issues and territorial disputes,” he said. “Currently, their three-way defence ties remain at low-level security cooperation at best, involving military intelligence exchanges.” Lee Won-deog, a political-science professor at Kookmin University, said Lee’s remarks about Japan could “put a dampener on Seoul’s efforts to improve ties with Japan” following years of disputes over how to compensate victims of Japan’s 1910-45 colonial rule over Korea. “The remarks concerning Japan could be aimed at stirring up voter sentiments in the election year,” he said. Lee also said disputes about a further deployment of THAAD interceptor missile batteries or its radars in the South had lost much relevance due to US technical breakthroughs in integrating its global missile defence systems. US and China not turning inward for good: Singapore minister As to a question about the course of action South Korea would take amid mounting rivalry between the US and China , Lee Jae-myung said: “There is no need to choose between the two.” “We can’t deny the fact that the United States is our close ally and we both are free democracies. The alliance with the US should continue being the basis of our diplomacy,” Lee said. “However, it would also be a dangerous thing for us if we abandoned China,” he said, adding China was geographically close and the two countries enjoyed “strong and ever-expanding” economic ties.