Vice President Dick Cheney has asserted his office is not a part of the executive branch of the U.S. government, and therefore not bound by a presidential order governing the protection of classified information by government agencies, according to a new letter from Rep. Henry Waxman, D-Calif., to Cheney. Bill Leonard, head of the government’s Information Security Oversight Office (ISOO), told Waxman’s staff that Cheney’s office has refused to provide his staff with details regarding classified documents or submit to a routine inspection as required by presidential order, according to Waxman. In pointed letters released today by Waxman, ISOO’s Leonard twice questioned Cheney’s office on its assertion it was exempt from the rules. He received no reply, but the vice president later tried to get rid of Leonard’s office entirely, according to Waxman. Leonard did not immediately respond to requests for comment. In a statement e-mailed to the Blotter on ABCNews.com, Cheney spokeswoman Megan McGinn said, "We are confident that we are conducting the office properly under the law.” As director of the tiny, 25-person Information Security Oversight Office, Leonard is responsible for keeping track of the nation’s secrets and making sure they are properly protected. For the first two years of the George W. Bush administration, Cheney’s office complied with a presidential order that requires officials to report statistics on the number of documents it classifies and declassifies. Since 2003, however, Cheney’s office has refused to submit the data to ISOO. And when ISOO inspectors tried in 2004 to schedule a routine inspection of the vice president’s offices, they were rebuffed, Waxman’s letter claims. Other White House offices, including the National Security Council, did not object to similar inspections, according to Waxman. "Serious questions can be raised about both the legality and advisability of exempting your office from the rules that apply to all other executive branch officials," Waxman said in his letter to the vice president, and asked him to explain why he felt the rules didn’t apply to him and his staff and how he was protecting classified information in his office. Former Cheney aide I. Lewis "Scooter" Libby was recently convicted on several counts of perjury and obstruction of justice stemming from the leak of the identity of former covert CIA officer Valerie Plame, Waxman noted, and in 2006, former Cheney aide Leandro Aragoncillo pleaded guilty to sharing classified U.S. documents with foreign nationals. Aragoncillo also worked under former Democratic Vice President Al Gore, who complied with ISOO’s requests. Do you have a tip for Brian Ross and the Investigative Team?