Defense Secretary Mark Esper Will Not Comply With House Subpoena

Defense Secretary Mark Esper decided not to comply with a House subpoena related to the impeachment inquiry, citing legal and practical concerns, including the lack of a full House vote and executive privilege. Initially, Esper had expressed willingness to cooperate. Other officials, including Vice President Mike Pence and Rudy Giuliani, also did not meet the subpoena deadline.

What did the Pentagon's letter to the House committees indicate?

How did Esper initially respond to the subpoena before changing his stance?