CNAS did a very well publicized wargame on the balance of power across the Taiwan Straits. The full write up is here. I think there’s good reason to believe that the Biden administration believes that a combination of the war in Ukraine and the steadily increasing maritime power of China have necessitated a clearer statement of purposes with respect to Taiwan. I have opinions, of course.
The purpose of making a deterrent threat is to prevent war. Asserting that the United States would come to the defense of Taiwan is intended to dissuade China from an invasion. Historically, the purpose of ambiguity was to deter both Beijing and Taipei, the former from an invasion and the latter from a declaration of independence that would amount to a virtual declaration of war. This delicate balance has held for nearly forty years, but it shouldn’t be thought of as a policy frozen in amber. Adding to either side of the scale can upset the balance and call for a new approach to policy. And there is no doubt that at least one element is rapidly changing; Beijing has significantly increased its military capabilities over the last decade, to the extent that a re-evaluation of the balance is now necessary.