This is a technical decision about appealing the decision.
Executive privilege generally
allows the president and his close advisers to refuse to produce documents or testimony to the judicial or legislative branches under some circumstances. The exact parameters of the privilege are still very much in doubt because the overwhelming majority of executive privilege claims have been resolved by negotiation rather than court order. This is not surprising, given that most privilege claims are intensely political, and courts have
created a doctrine to avoid ruling on intensely political questions.
The Constitution says nothing about executive privilege, but the concept became evident very shortly after the founding. Discourse on the subject has been heated and political from the start. In 1792, President Washington and the very first Cabinet
decided on a policy of producing documents in response to congressional document requests only if the executive considered it in accordance with “the public good.” Washington continued to follow that policy, and he also did not produce documents when he deemed the request not in accordance with the Constitution.
Subsequent presidents continued using that standard, including President Jefferson when he refused to produce documents and testimony for Aaron Burr’s impeachment trial. The first significant judicial
shaping of executive privilege came in 1974 when President Nixon attempted to assert executive privilege to prevent the release of secret tapes, transcripts, and meeting memoranda. The Supreme Court
ruled 8-0 that Nixon had to produce the evidence because executive privilege, while constitutionally valid, could not be absolute or unqualified. The Supreme Court’s standard in 1974 was not much clearer than George Washington’s in 1792: “the legitimate needs of the judicial process may outweigh Presidential privilege.”