Affirmative Action was going to be unconstitutional anyway as of June 23, 2028, so all this will do is move up the clock a bit.
What about that date specifically?
On June 23, 2003 the Supreme Court issued their Grutter v. Bollinger which upheld affirmative action based on a 5-4 decision with Sandra Day O'Connor joining the liberals. However O'Connor wrote a bit of an odd decision, she said that affirmative action is justifiable due to systemic issues in society but also said that in time these could be resolved and it would no longer be necessary. And then the kind of weird and very Sandra Day O'Connor-ish thing she did was set an actual deadline: stating 25 years from now affirmative action would no longer be necessary. So being the median vote that set the precedent: affirmative actions is legal and constitutional, but only for 25 years years from the point of that decision being written, hence until June 23, 2028.
What O’Connor’s opinion says, specifically, is “We expect that 25 years from now, the use of racial preferences will no longer be necessary to further the interest approved today.” So the Court didn’t set a hard deadline after which affirmative action automatically becomes illegal. Rather, they expressed an expectation, a hope, i.e. “let’s revisit this issue again in 25 years and see if the reasoning still holds up or not.”