Do we have a defense treaty with Taiwan? If not, we’d better sign one. And arm the Japanese.
“Do we have a defense treaty with Taiwan?”
I certainly hope not. Not our problem.
The Taiwan-American defense treaty was abrogated in 1979 when Jimmy Carter and both houses of Congress sold out to Communist China, broke diplomatic relations with Taiwan, and recognized Communist China instead.
It was replaced with the Taiwan Relations Act, which is not a full mutual defense pact. On the other hand it is not insignificant either. In time of peril, such as now, its strength will depend on the interpretation of the president at the time. The presidency of Donald Trump has been favorable to strengthening Taiwan, but its commitment in case of open hostilities is unknown.
The Taiwan Relations Act does not guarantee the USA will intervene militarily if the PRC attacks or invades Taiwan nor does it relinquish it, as its primary purpose is to ensure the US's Taiwan policy will not be changed unilaterally by the president and ensure any decision to defend Taiwan will be made with the consent of Congress. The act states that "the United States will make available to Taiwan such defense articles and defense services in such quantity as may be necessary to enable Taiwan to maintain a sufficient self-defense capabilities". However, the decision about the nature and quantity of defense services that America will provide to Taiwan is to be determined by the President and Congress. America's policy has been called "strategic ambiguity" and it is designed to dissuade Taiwan from a unilateral declaration of independence, and to dissuade the PRC from unilaterally unifying Taiwan with the PRC.
The act further stipulates that the United States will "consider any effort to determine the future of Taiwan by other than peaceful means, including by boycotts or embargoes, a threat to the peace and security of the Western Pacific area and of grave concern to the United States".
This act also requires the United States to have a policy "to provide Taiwan with arms of a defensive character", and "to maintain the capacity of the United States to resist any resort to force or other forms of coercion that would jeopardize the security, or the social or economic system, of the people on Taiwan." Successive U.S. administrations have sold arms to Taiwan in compliance with the Taiwan Relations Act despite demands from the PRC that the U.S. follow the legally non-binding Three Joint Communiques and the U.S. government's proclaimed One-China policy (which differs from the PRC's interpretation of its one-China principle).