The answer to the question posed in the title to this post is immediate from anyone who has sought to set aside a plea based on later-discovered evidence of innocence, police misconduct, prosecutor misconduct or a change in the law that has retroactive effect. However, to most people, the question may only trigger a blank stare. To read why a factual basis for a plea is important, please click on the following link.
https://www.greghillassociates.com/why-is-a-factual-basis-for-a-plea-important.html.