WASHINGTON (Reuters) - The Justice Department and the special counsel investigating the leak of a CIA operative's identity pressed Congress to block legislation that would compel the administration to turn over documents related to the case, the department said in a letter released on Thursday. The Justice Department, in a letter dated September 14, said special counsel Patrick Fitzgerald had advised that producing documents and holding hearings would interfere with his investigation. The letter was sent to the House Intelligence Committee's Republican chairman, Rep. Peter Hoekstra of Michigan. Congressional Democrats have so far failed in their attempts to pass legislation...