a Tokyo Metropolitan Government adviser and former lieutenant general, said that part of the rationale for the fifth M-V Hayabusa mission, from 2003 to 2010, was that the re-entry and landing of its return capsule demonstrated "that Japan's ballistic missile capability is credible." A Japanese nuclear deterrent would probably be sea-based with ballistic missile submarines. In 2011, former Minister of Defense Shigeru Ishiba explicitly backed the idea of Japan maintaining the capability of nuclear latency: On 24 March 2014, Japan agreed to turn over more than of weapons grade plutonium and highly enriched uranium to the US, which started to be returned in 2016. It has been pointed out that as long as Japan enjoys the benefits of a "nuclear-ready" status held through surrounding countries, it will see no reason to actually produce nuclear arms, since by remaining below the threshold, although with the capability to cross it at short notice, Japan can expect the support of the US while posing as an equal to China and Russia. Former Mayor and Governor of Osaka Tōru Hashimoto in 2008 argued on several television programs that Japan should possess nuclear weapons, but has since said that this was his private opinion. Former Governor of Tokyo 1999-2012, Shintaro Ishihara was a advocate of Japan having nuclear weapons. On 29 March 2016, then-U.S. presidential candidate Donald Trump suggested that Japan should develop its own nuclear weapons, claiming that it was becoming too expensive for the US to continue to protect Japan from countries such as China, North Korea, and Russia that already have their own nuclear weapons. On 27 February 2022, former prime minister Shinzo Abe proposed that Japan should consider a nuclear sharing arrangement with the US similar to NATO. This includes housing American nuclear weapons on Japanese soil for deterrence. This plan comes in the wake of the 2022 Russian invasion of Ukraine. Many Japanese politicians consider Vladimir Putin's threat to use nuclear weapons against a non-nuclear state to be a game changer. Although an indigenous nuclear program in Japan is unlikely to develop due to low public support, the existential Chinese and North Korean threats have raised security concerns domestically. The role of public opinion is central, and studies show that threat perceptions – mainly of China’s growing military abilities – have strengthened Japanese public support for a nuclear program. Japan has long held negative views on nuclear weapons, and previously,