ABOARD THE USS INDEPENDENCE, SEPT. 6 -- As U.S. military officers and enlisted personnel contemplate the possibility of the country's first sustained conflict since Vietnam, the divisive experiences of the last war appear fresh in their minds, affecting the way officers describe the military mission to their men and shaping the way servicemen think about their jobs.

Naval officers say that in the post-Vietnam world, they are more conscious about defining and repeatedly articulating the goals of their mission and the effects of the Persian Gulf crisis on friends and family back home. They also appear deeply sensitive to shifting currents in U.S. public opinion, searching in news reports and in contacts with outsiders for any signs of disenchantment with their presence in the gulf.

A few days ago, Capt. Robert Ellis, a senior commander on this aircraft carrier in the Gulf of Oman, saw some political cartoons from American newspapers that disturbed him. The cartoons suggested that he and the 5,000 men aboard the Independence had been sent to the Middle East mainly to fight and die for the cause of oil.

Ever since, Ellis has been mulling over ways to talk about the issues of oil supplies, recessions and the interdependence of the world economy in a speech to the seamen and aviators under his command. He wants to explain, he said, that "oil and energy drive the economies of the world" and that if supplies are interrupted, the emerging democracies in Eastern Europe, as well as U.S. allies such as Japan and Germany, will suffer badly.

It is, he concedes, "a very complicated message of leadership."

But Ellis's instinct that the servicemen on the front lines of the Persian Gulf crisis are interested in such complications appears sound. Below decks, around the time Ellis saw the cartoons that bothered him, some of the carrier crewmen gathered around radios to listen to President Bush's speech to the armed forces about why vital U.S. interests are at stake in the gulf. When the president referred to the need for a national energy policy, some of the seamen got into a vigorous discussion about why an energy policy to reduce U.S. dependence on imported oil was not already in place.

"It's a very valid question," said Jim Pratt, a 31-year-old enlisted man. But after hashing the issues out with his friends, Pratt has concluded that "we've got a purpose here." Officers and crew alike say they are greatly buoyed by the outpouring of domestic and international support so far for President Bush's decision to deploy tens of thousands of troops to Saudi Arabia and the gulf. But they worry about how long that support can be sustained and whether a new cycle of public anger over military entanglements will begin if war breaks out.

"Right now, I like what I've seen and heard," said Dave Beverly, a weapons officer who flies F-14 Tomcat fighter jets from the decks of the Independence. "But one thing that concerns me is how long we'll have that support. . . . To me, that's a big concern from home."

Recently, a U.S. news program's interviews with high school students were shown on board. The students worried about being drafted and said they felt the weight of the gulf crisis on their shoulders. "We were surprised to hear that they felt pressure," one pilot said.

Still, mid-level officers and enlisted men suggest in interviews that they are confident the lessons of Vietnam have been learned. The problems in Vietnam, said Tomcat fighter pilot Charlie Haden, were "lack of commitment, lack of purpose, lack of a goal. I'm hoping the lesson we learned then is to define our goal -- like we're doing now."

Senior officers here and on other ships plying gulf waters say they have emphasized open communications with their men, encouraging the distribution of news reports and television talk shows from the United States and making frequent impromptu speeches about the nature of U.S. interests in the gulf region. When U.S. reporters are flown to ships such as the Independence, press conferences with senior officers are broadcast live to the crew on a closed-circuit television network.

The purpose of such frequent political dialogue, Ellis said, is to "let the people make their own decision . . . although I hope the way I articulate the issues leads them in the same direction."

In the present crisis, the "strong economic and moral case" that Ellis believes is on his side appears to be an easy sell. While officers and enlistees disagreed in interviews about which aspect of the gulf crisis is most important -- protection of world oil supplies, the defense of Saudi Arabia, the liberation of Kuwait or the freeing of U.S. hostages held by Iraq -- many of them appear to have been galvanized by enmity for Iraqi President Saddam Hussein.

Fighter and bomber pilots discuss the question of flying missions into Iraq if the "human shield" erected by Saddam around key installations remains in place.

The ship's air wing commander said that while he considers Saddam's tactic "dirty pool," he and other flyers will put the matter out of their minds if the time comes. He said that while flying sorties during the Vietnam War, he and other pilots sometimes had to drop bombs near U.S. soldiers in order to roll back attacking Vietnamese forces. Sometimes such quandaries are a necessary part of war, he said.