SOUTH VIET NAM PLEASE SEND ORDERS IN THE TWO MONTHS SINCE THE OVERTHROW OF PRESIDENT NGO DINH DIEM, THE NEWS OUT OF SOUTH VIET NAM HAS BEEN MOSTLY BAD . THE COMMUNIST VIET CONG HAVE SCORED ALARMING GAINS IN VITAL LONG AN PROVINCE SOUTH OF SAIGON, WHICH FEEDS THE CAPITAL . FOR ALL THE FANFARE WITH WHICH THEY WERE WELCOMED BY DIEM'S CRITICS, THE GENERALS WHO SUCCEEDED THE SLAIN PRESIDENT HAVE DEMONSTRATED AN UNSETTLING LACK OF POLITICAL LEADERSHIP; RECENTLY, THE CIVILIAN CHIEFS OF NINE NORTHERN PROVINCES RELAYED A PLEA TO JUNTA CHAIRMAN MAJOR GENERAL DUONG VAN ("BIG") MINH: "PLEASE SEND US ORDERS ." LAST WEEK U.S . DEFENSE SECRETARY ROBERT S . MCNAMARA FLEW FROM THE NATO MEETING IN PARIS TO SAIGON, FOR HIS SECOND VIET NAM INSPECTION VISIT IN THREE MONTHS . JOINED BY U.S . CENTRAL INTELLIGENCE AGENCY CHIEF JOHN A . MCCONE, MCNAMARA PLUNGED INTO BRIEFINGS AT THE U.S . MILITARY MISSION . THEN HE SPENT AN AFTERNOON CONFERRING WITH BIG MINH AND THE OTHER JUNTA CHIEFS . UNDER DISCUSSION WERE PLANS FOR A MAJOR NEW OFFENSIVE AGAINST THE VIET CONG . BEFORE BOARDING HIS PLANE FOR HOME, MCNAMARA TURNED TO VIETNAMESE DEFENSE MINISTER MAJOR GENERAL TRAN VAN DON WITH SOME STERN WORDS OF ADVICE . "NOW," SAID MCNAMARA, "LET'S BE REAL TOUGH ."