Did requiring the assertion of detail known only to the government to show 'materiality' impermissibly raise the threshold?

QUESTION PRESENTED At trial, the petitioner sought to prove the existence of two separate conspiracies. One in Ohio and the other in Tennessee. During discovery, the petitioner was given a copy of a “sealed” affidavit describing the government's Ohio investigation but refused. The detail in the affidavit was offered to establish the “materiality” of the undisclosed information. The Court of Appeals held that to establish “materiality”, the petitioner must offer more than the content of the “sealed” affidavit and its implications. Did requiring the assertion of detail known only to the government to show “materiality” impermissibly raise the threshold? I