Amid worsening strategic circumstances, leaders including the late Abe Shinzo have led the charge for Japan to increase its national and collective defence abilities. Given Japan's closeness with Australia and the US, it has been suggested that Japan might join the AUKUS arrangement. So, what is stopping Japan from joining AUKUS? Hayley Channer asks Kei Koga, Japan Fellow at the Wilson Centre and Assistant Professor at Nanyang Technological University in Singapore.