both the United States and China. During the 1995–1996 Taiwan Strait crisis, then President of Taiwan, Lee Teng-hui, proposed to reactivate the program, but toned down the rhetoric a few days later, saying that although Taiwan was nuclear latent, it "will definitely not" produce nuclear weapons. There is no evidence that Taiwan possesses any nuclear weapons or any programs to produce them, although it does have the advanced technological ability necessary to develop nuclear weapons as well as the high-tech ability to enrich uranium or process plutonium. Taiwan's nuclear power plants use imported enriched uranium and are subject to IAEA inspections. Taiwan theoretically has the potential to develop nuclear weapons from domestic monazite reserves, and this potential was explored by the military in 1951–1952. However, the monazite's thorium content was deemed too low to justify recovering, and the military turned to friendly foreign sources instead. In light of rising tensions in Cross-Strait relations, especially after Russia invaded Ukraine in 2022, some have called for Taiwan to arm itself with nuclear weapons, especially commentators in the United States. This is subject to wide debate, with some arguing that nukes could prove a deterrent strong enough to force the mainland to indefinitely postpone an invasion, given that Taiwan is not like Japan and South Korea in that they have treaty-bound security guarantees from the United States, though opponents argue that nukes in themselves are costly, unpopular among the Taiwanese public, and that they themselves would instigate a conflict. Chemical and biological weapons During the Japanese colonial period a chemical weapons factory was in operation in North Taiwan; the Nationalists took possession of this facility following the conclusion of World War II and are believed to have expanded the facility. The U.S. Congress was informed in 1989 that Taiwan could have acquired offensive chemical weapons capability, including stockpiles of sarin. The alleged facilities include Tsishan and Kuanhsi. Taiwanese authorities acknowledged only the existence of a defensive research program. In 1997 the Russian Foreign Intelligence Service assessed that Taiwan did not possess biological weapons but had "shown signs of conducting biological research of an applied military nature.” There have been rumors of ongoing offensive and defensive Taiwanese biological and chemical weapons programs but no conclusive evidence of development or deployment has ever been presented. Ratification of international treaties The Republic of China ratified the Geneva Protocol on August 7, 1929, and the Nuclear Non-Proliferation