The sudden and much publicized arrival of U.S. troops on an anticocaine mission has stunned and offended many Bolivians, throwing President Victor Paz Estenssoro on the political defensive and engendering widespread skepticism about the operation's ability to stem the drug trade here.

The scale of the U.S. participation and its high visibility, including publicized photographs of armed American Black Hawk helicopters landing and U.S. personnel in battle fatigues, have complicated efforts by Bolivian officials to portray the operation as Bolivian-organized and directed, with the Reagan administration providing only logistical support.

Politicians on the left and right have attacked the U.S.-Bolivian venture, accusing the Paz Estenssoro government of compromising national sovereignty by inviting American troops and of violating the constitution by failing to consult Congress beforehand.

More critical to the country's civil peace, labor and peasant union leaders are considering mass protests. They are concerned about damage to the lucrative coca industry coming at a time when Bolivia's crucial mining sector is depressed and an unpopular tax-raising plan is soon to be introduced.

Bolivian and U.S. officials had hoped to expose several giant cocaine-processing laboratories in the first raids. Early successes were thought important to give the operation momentum and deflect expected criticism of the U.S. role.

But three of the initial four strikes on Friday and yesterday yielded nothing, apparently because of poor intelligence about the location of presumed labs. Operations were suspended today due to low clouds and rain over the Beni region where the cocaine factories are beingsought and raided.

While the government had asked months ago for the U.S. airlift, operational planning had been in such flux that many of those here who were involved did not know until the last minute what the number of U.S. military personnel would be. Unaccustomed to seeing the American Army in action, Bolivian authorities have been startled by the length of the logistical train set up.

"U.S. Invades Bolivia," declared a headline in Aqui, a Bolivian tabloid, echoing the sense many here expressed in watching the Americans swing into position. Such press coverage has upset government officials, who apparently had not anticipated the intense media interest that would be generated from the start by the arrival of 160 drug-fighting U.S. soldiers.

"We think the whole thing has been blown out of proportion," Information Minister Herman Antelo complained at a press conference in La Paz yesterday. "We're losing sight of the main objective: the repression of narcotics trafficking."

"I am in agreement with the operation, but I would have been more in accord with it had we been given the financing and infrastructure to manage it ourselves," said Jacobo Libermann, a writer and longtime friend of Paz Estenssoro who serves as a presidential adviser. He said he did not have advanced knowledge of the antidrug raids.

The government has defended its decision, saying the U.S. participation is only "technical" in nature and serves a "police" rather than a "military" function. It has stressed that members of Bolivia's special antinarcotics police force are doing the actual seizing of facilities.

In the four raids reported so far, U.S. Army pilots are said to have remained in their helicopters after transporting police to target sites.

The Americans, however, outnumber the Bolivians in the operation. Informed sources say the Bolivian police contingent totals about 80 members of the Mobile Rural Patrol Unit -- the official name of Bolivia's antinarcotics strike force, more commonly known as the Leopards. The unit, which now has about 650 members nationwide, is itself the product of a three-year-old U.S.-funded program. Bolivia's U.S.-backed antidrug effort is viewed as an economic threat by hundreds of thousands of peasants whose livelihood depends on the legal cultivation of coca leaves and who use coca as a key dietary supplement. Bolivians have chewed the coca leaf for centuries, consuming it as a mild narcotic against hunger, cold and illnesses.

"For us, coca is like milk for a baby," said Sylvia Camacho, 35, who spends weekends in an outdoor market in Cochabamba selling sacks of coca leaves, which go for about 85 cents a pound.

Leaders of several dozen peasant groups organized a protest rally yesterday in Villa Tunari, a town in the heart of the coca-rich Chapare region, denouncing the anticocaine operation and appealing to the government for greater economic assistance in weaning Bolivia more gradually off coca production.

"We're not in accord with the narcotics traffickers, but the government has not done enough to explore other commercial uses for coca, such as analgesics, and soft drinks," said Johnny Quiroga, an officer of a peasant cooperative headquartered in Cochabamba. "Nor has it met our demands for electricity, schools and better roads in the Chapare that would help make other types of crops work in that region."

Centrist Sen. Mario Mercado said: "Within one year, the laboratories will be functioning again. This is a Band-Aid, not a cure. The only thing that will work is to find a substitution for the millions of dollars that the drug trade brings into the country."

Some traffickers are reported to have fled Bolivia, apparently tipped about the raids even before the first Bolivian press reports.