THE OIL-DEPENDENT travel world is looking at the 1980 tourism through rose-colored glasses while keeping fingers crossed. And there's the bitter smell of boycott in the air.

More than $500,000 is being spent this year by the 23-nation European Travel Commission to promote travel to Europe, but even the most optimistic brochure printers are estimating only a few-percent increase over last year in the number of Americans who go sightseeing overseas.

Looking at the bright side, the ETC is again emphasizing the savings available to cost-conscious tourists through prepaid package tours. The prices for land arrangements (hotels, meals, sightseeing) in some cases can be guaranteed in advance of departure against surcharges due to currency fluctuations of other causes.

Many countries have lauched their own campaigns to tout their attractions ("Belgium The Surprise Package of Europe," "Affordable Norway"). The British Tourist Authority, alone and in cooperation with airlines, will spend $2 million on U.S. advertising to convince us we can "still afford Britain."

Just about every country from Argentina to Zaire wants visitors, and the cash register-jingling foreign exchange they bring with them. Egypt and Israel remain bright hopes for Mideast travelers (nonstop, regularly scheduled air service between Tel Aviv and Cairo began last Monday), and the Peoples Republic of China has been one of the biggest travels surprises in decades.

Unfortunately, however, not every country is in the best of conditions to welcome tourists, although it is rare for a country to admit it may be bent out of shape for reasons such as actual or incipient revolution, political killings in the streets, racial turmoil, or just plain lack of adequate facilities and a warm welcome. Most American travelers no longer expect to be loved by all foreigners; they do, however, expect to be treated fairly and to feel safe.

Certainly you haven't seen any convincing promotional material lately for Iran, El Salvador to the State Department's Bureau of Consular Affairs, Overseas Citizens Services (202-632-3816), about 20 countries presently are on a list of areas the government basically recommends as suitable for "only essential travel." Fifteen of these are in the Middle East (mostly Moslem countries), two are in Latin American (El Salvador and Nicaragua), and three are in Africa (Chad, Uganda and Rhodesia). The list can change almost overnight, and some doubtful tourist destinations arae never mentioned. In some instances the situation is "more sticky," a spokesman added. In the case of Afghanistan, for example, Americans are bluntly "urged to avoid" going there.

Of course, tourism is spoken of -- quite legitmately, too -- not merely in crassly commercial words but in terms of peace, friendship, brotherhood and world understanding (among people, at least, if not governments).

For a little while it seemed we were facing another "normal" international summer high season, with the dollar still doing its death-defying nosedive in the money markets abroad while the cost of room and board continued to soar. Then gold and silver traders raised the ante, and after anyone had just about become resigned to living with higher gasoline prices and air fares, and energy surcharges on some hotel rooms and cruise ships, the kill-joys really started pouring oil on troubled waters.

The shah of Iran was forced to flee his kingdom, Iranian terrorists invaded the U.S. Embassy in Tehran and took our diplomatic personnel as hostages, and finally the Soviet army invaded Afghanistan. Cross Tehran and Kabul off your spring and summer itineraries.

Then the president of the United States spoke the word that can cause a government tourism office or any travel agent to tremble: Boycott. The president was advocating a boycott of the Moscow Summer Olympics by this country -- and by any other free nations that would support it. He was not talking about U.S. tourists boycotting travel to the Soviet Union, but it was inevitable that such an unmentionable subject would soon be mentioned in travel circles and in letters to the editor.

It is easy to sympathize with Americans who prepaid million of dollars for their Olympic games tour packages to Moscow, and now stand to lose both the trip and a portion of their investment, the actual amount to be determined by a court in the event the U.S. Olympic Committee does indeed carry out the boycott Presidential Carter has urged.

It is even easy to commiserates with those U.S. tour operators and travel agents who have asked our government to indemnify them for financial losses they will suffer because of such a boycott.

While it is easy to feel very sorry for the innocent and bitterly disappointed athletes who cannot be repaid for losing their chance to compete, I have no sympathy for those Olympic officials who refuse to understand or admit what has already happened to besmirch those lofty Olympic ideals of true amateurism, and who cannot face the incontrovertible political fact so clearly stated by exiled Russian dissident Valentin Turchin:

"I think if the Olympic Games happened to be in Montreal nobody would think of it as sort of a vindication or jusitifaction or legitimization of their political system. But for the Soviet Union it is so. . ."

And that is precisely why, I believe, many American travelers are rethinking previous plans to visit the Soviet Union this year. According to Alex Harris, president of General Tours in New York, "a de facto ban already in effect on travel to Russia. If that situation hardens in coming months, it will not be the first time Americans have decided to change plans in protest.

Harris is leading a drive by tour operators who specialize in Soviet Union packages to convince the U.S. government it should give "direct financial aid" to such firms to help offset their expected massive losses.

Harris said the tour operators were "extremely disturbed" by the lack of government response to their plea so far, beyond a statement of "regret" that the industry will suffer because of actions taken "by the Soviet Union." Referring to government promises to help farmers weather the economic effects of the president's embargo on grain shipments to Russia, Harris said unfortunately the travel industry doesn't have a "a lobby" like the farmers.

Last year about 100,000 U.S. travelers visited the U.S.S.R., Harris said. This year the total might have reached 130,000 inclucing approximately 20,000 headed for the Olympics, according to Harris. But earlier U.S. retaliatory moves against Russia caused tour operators to reduce their estimated to 60,000 visitors.

Now Harris believes the effect of an Olympic boycott would be to slash that figure to a mere 20,000 bookings. That would reduce the 1979 figure of $165.5 million in Soviet bookings by the U.S. travel industry during "detente" to only $34 million during a boycott.

Even the cruise lines are becoming involved. Royal Viking Line has already dropped three Russian ports from the itinerary of what was originally billed as a Mediterranean/Black Sea cruise departing April 14. It has also drawn up a list of alternate ports for other cruises, to avoid docking in Soviet territory, but is waiting to gauge passenger reaction before deciding whether to make the changes. Other lines, sensitive to the controversy, are reportedly also considering eliminating Russian ports from future sailings.

When profits and prestige are tied together, the aggressive, status-conscious Russian bear can be expected to suffer far more than the disappointed tourists, athletes and tour operators. He is already growling and gnashing his teeth, and not a single U.S. soldier is involved.

But how long will the American traveler remember the Russian invasion and the Iranian blackmail? And how long should he remember? Neither question lends itself to a simple answer.

Assuming U.S. tourists do indeed refuse to travel to Russia, will it be in support of the Afghan freedom fighters or merely a knee-jerk reaction? Will our Western allies and other countries give tangible support to an Olympics boycott? Will the president change his mind again?

When the "student" terrorists in Tehran finally release our diplomatic personnel, what shall we consider a "decent interval" (something like when a widow remarries, perhaps?) before once again we take our dollars, however, weak, back to "Lovely Isfahan" and Darius the Great's Persepolis? (Assuming, of course, that when the fanaticism and hysteria subside, Iranians will still want U.S. tourists and will be able to accomodate them in 20-century, not 7th-century, style.) Or will Americans be left with such a sense of outrage that Iran will be a forgotten travel destination for many years to come?

It is often in our national interest for our government to deal with lunatics and dictatorships, however unsavory. And our diplomats must shake hands with the devil, if necessary, while keeping careful count of their fingers. But tourists are not paid to dissimulate -- they pay for everything.

Those who generally oppose any kind of travel boycott say with much logic that if a traveler starts crossing countries off his or her list because of displeasing political factors, there would soon be very few countries left to visit. They also argue that the boycotting tourist is denied an opportunity to learn firsthand about current conditions, and that boycotts may invite retaliation in kind. (But at least they don't kill people, and they don't requre armies.)

Although the State Department shared the dollar-conscious travel industry's dim view of private citizens playing international politics, who is to say that one traveler may not withhold still-prized dollars from the Soviet Union to protest violations of basic human rights? Or that another may not cross South Africa off his list because of its institutionalized discrimination against blacks?

If we decide we are going to punish our enemies this year by staying away, will we not conversely reward our friends like Canada (she of the "Great Tehran Hostage Escape" gambit) by pouring over her friendly border in uncounted numbers?

And speaking of enemies, how many years did it take before our once-mortal enemies, Germany and Japan, became our friends and began competing peacefully with us in almost every field -- including tourism?

When you come right down to it, that points up the real problem of dealing with a dangerous concept like a boycott in the field of international travel. Except in wartime, our government often has a terrible time reorganizing and cultivating potential friends and dealing intelligently and firmly with potential enemies.

So if the government is confused, don't expect political answers from your travel agent. The agent, at least, will always have plenty of colorful, tempting brochures. Pick up a pair of rose-colored glasses, spin the globe, open your wallet and remember that, thankfully, travel is still fun.