The reason for this gap, Justice Barrett and the majority insist, is that the federal courts themselves only have powers allocated to them by the constitution and federal law.
They’re coming for Marbury v Madison.
Edit: Context
https://en.wikipedia.org/wiki/Marbury_v._Madison
Marbury v. Madison, 5 U.S. (1 Cranch) 137 (1803), was a landmark decision of the U.S. Supreme Court that established the principle of judicial review, meaning that American courts have the power to strike down laws and statutes they find to violate the Constitution of the United States. Decided in 1803, Marbury is regarded as the single most important decision in American constitutional law.
If Marbury is overturned, this means that whatever laws (or executive orders or whatever) get passed are law, with disregard as to whether they are constitutional. If Marbury is overturned, the Constitution is literally destroyed.