"Life goes on" is a favorite expression of President Bush as he goes through the most trying moments of his White House tenure.

On Monday, he will mark his second year in office with his political future highly dependent on the outcome of the war.The 66-year-old president has put on his commander-in-chief cap but he is not assuming a tactical role. Rather he is leaving to the Pentagon experts management of the war and the plotting of its course in the battle to drive Iraq out of Kuwait. He is not an armchair general.

As it is with all presidents in times of crises, the ordeal is beginning to take its toll. In recent days since he made the fateful decision that force was the only way to contend with Iraq's Saddam Hussein, Bush has looked tired, his face drawn and the lines deeper.

He has not been getting his usual six or seven hours' sleep, and the telephone calls will be interrupting his sleep in the middle of the night from now on until the war is over, especially with the clock eight hours ahead in the Persian Gulf.

Bush made the command decision to go to war on Tuesday when he signed a top-secret document. On Wednesday, he inserted the date on the order sending troops into combat.

One of the few people he confided in was his wife, Barbara, who was told in advance. She has indicated that she did not envy her husband and his burden.

Bush has established a good working rapport with his advisers. They are a close coterie and none apparently assumes the posture of the devil's advocate, a role played to no avail by former Undersecretary of State George Ball with Lyndon B. Johnson during the Vietnam War. Johnson had no use for doves at that time.

Everyone apparently was on board with the president when he felt he had run out of diplomatic initiatives and turned to the sword.

In recent statements he has shown a certitude in the correctness of his course and aides say there is no agonizing or Monday morning quarterbacking on his part.

Bush has been briefed regularly by national security adviser Brent Scowcroft since the start of the Persian Gulf hostilities. He also receives reports from the "24-hour situation room" in the basement of the West Wing, which he occasionally visits.

When the first film footage of the air strikes against Baghdad were shown, Bush was glued to the television set. He also got into the spirit by asking for a copy of "Intruder in Flight," a movie about the bombing of Hanoi during the Vietnam War, to get in the mood.

It was reminiscent of Richard Nixon's addiction to the film "Patton, " which he viewed several times while engaged in the Southeast Asia conflict.

In the image department, there have been some manifest touches. The president sought spiritual guidance from evangelist Billy Graham and went to a special service at a nearby military chapel arranged by Graham.

During recent news conferences, Bush is flanked by the American and presidential flags at the podium in the White House press room.

Otherwise, Bush has kept his public appearances to a minimum and invokes the "no questions" rule at times and at other times is anxious to make a comment.