SC is required to take all law into account as broadly as possible to support. They're legally required to "throw a bone." They can't say something is unconstitutional just because the wrong argument was used at the time. You can argue they don't know about it or didn't refer to it, but at this point, there's legal precedent so it very likely will not work.

Edit: when has the threat to expand the court worked?

Edit: and Dems don't have majority to expand the court anymore anyway