Fed up with giant ships that discharge waste into their waterways and with tourists who flood their downtown, residents of Juneau, the state capital, in early October approved a $5 tax on every passenger. A bit farther north, the small town of Haines voted to limit the number of cruise ships allowed at its dock. And some Juneau residents have called for one cruise line to be barred from the state's waters.

But the Alaskans who are fighting to restrict the booming $12 billion cruise ship industry have a powerful opponent they may not have expected: their own representatives in the United States Congress.

At every juncture, efforts to slow the industry's expansion in Alaska have been blocked by members of the state's Congressional delegation, all three of whom are Republicans and chairmen of committees with wide influence over both the state and the industry.

In the last three years, the Alaska delegation has, among other actions, opened the way to allowing more ships into the environmentally delicate waters of Glacier Bay National Park, stymied federal efforts to consider stricter antipollution standards for ships and overridden a state law prohibiting shipboard gambling in Alaska waters.

Some of the actions were legislative sleights of hand, adding amendments to bills after public discussion had ended. In some cases, people here do not even know what their representatives have done for the industry. Other actions were exercises in political muscle by an influential Alaska tag team, Senator Frank H. Murkowski and Representative Don Young, the chairmen, respectively, of the Senate Energy and Natural Resources Committee and the House Resources Committee.

Mr. Murkowski, Mr. Young and their spokesmen contend that they are not protecting the cruise industry but promoting tourism in Alaska, where the economy has suffered from declines in the timber industry and a slackening of oil revenue. And many businesspeople throughout the region have applauded their delegation's efforts as loudly as environmentalists have condemned them, noting that the cruise industry has been crucial to the state's economy.

Cruise ship passengers spend more than $160 million a year in southeast Alaska, according to a 1997 study financed by the industry and the cities in the region. In Juneau, the influx of passengers has spawned dozens of businesses, from upscale art galleries to T-shirt shops, and helped rejuvenate the downtown area.

"There's been a very positive impact from the cruise ships," said Jack Cadigan, whose family owns three shops that cater to tourists.

Mayor Dennis Egan of Juneau agreed that the industry's growth had helped the economy, and he gave part of the credit to the state's Congressional delegation.

"They are friends of the industry, no question about that," said Mr. Egan, a Democrat. "And they have Alaskan issues at heart, too."

But the tensions have grown as the foreign-registered cruise companies have become a major leisure industry, with legislative protections that are the envy of American business, and as the Alaska delegation has played an important and little-understood role in helping to expand the number of ships and passengers visiting the state.

A look at the fight that has broken out here provides insight into that role, as well as into how the industry's ever-larger ships, some of them longer than three football fields, are beginning to stir a backlash in some communities. The struggle also reflects an age-old feud over Alaska's unrivaled natural resources. It echoes earlier battles between the timber and oil interests, who have often bristled at too much Washington meddling, and the environmentalists, whom some critics portray as uncompromising in the face of a struggling local economy.

Kimberly Metcalfe-Helmar, a second-generation Juneau resident and president of a downtown neighborhood group, was surprised and pleased by the vote to tax cruise passengers. Just three years ago, she had led an unsuccessful effort to pass an identical tax.

"I've been fighting this since the mid-80's, but it's only recently that the noise, pollution and dumping have galvanized the town," Ms. Metcalfe-Helmar said.

The tax was approved by nearly 70 percent of the voters. The margin of victory demonstrated how frustrated many of the people in this town of 30,000 have become with the 600,000 passengers who clog their streets each summer, and with the ships whose smokestacks send a hazy pollution snaking around the mountains that cradle the town.

But the backlash also reflected deep indignation over the admission by one company, Royal Caribbean International, that its ships had dumped hazardous waste within the Inside Passage, whose clear glacial waters wind gently through southeast Alaska and teem with salmon, halibut, king crab and whales.

The industry's reaction to the vote was swift. Princess Cruises, which brought about 180,000 passengers to Juneau this past summer, said its ships would shorten their stays next season, a decision that created anxiety among local businesses about lost revenue and led them to form a pro-tourism organization. The company also said it was canceling the one stop it had planned for next summer in Haines. Princess's representative here said the moves were intended to lessen the cruises' impact on the two towns.

Another cruise line took action that some people saw as clearly punitive. Holland America Line cut off donations to some charitable and civic organizations in Juneau, including the arts council and the Civil Air Patrol, and explained that the tax vote had prompted a "reassessment" of its relationship with the city. The local newspaper, The Juneau Empire, condemned the company for taking revenge on nonprofit groups.

Tensions may flare again when state regulators hold a public meeting here, scheduled for this Friday, to consider whether new restrictions are needed to curtail the activities of cruise ships. Such restrictions would again put backers at odds with industry stalwarts in Congress.

The cruise industry maintains a low profile in Washington, and its contributions to candidates for federal office from January 1993 through the end of October 1999 totaled $1.2 million, far less than those of many other interest groups. But an analysis of contributions by individuals and political action committees associated with the industry found that they have been most generous with the Alaska and Florida delegations, which makes sense given that the companies have their most important operations in those states.

The Alaska delegation, whose third member is Senator Ted Stevens, chairman of the Appropriations Committee, was the second-largest recipient of campaign contributions, with $117,950. Only Florida, which has 25 members in Congress and is also home to most of the cruise companies, got more: $230,701.

Mr. Young was the largest House recipient, with $69,500. Three years ago he played a pivotal role when a lucrative part of the industry's business was threatened.

Alaska law limits gambling to charities, which operate small-scale bingo games and raffles to raise money. In 1993 the state attorney general determined that the law extended into the waters the state controlled within three miles of shore and ordered cruise ships to shut down their casinos.

In most places, the order would not have had much impact, because cruises quickly escape the three-mile jurisdiction of American states and operate in international waters, where they are free of regulation.

But in Alaska the itinerary follows the Inside Passage along the rugged coast, and only several sections along the route, known as doughnut holes, are more than three miles from either shore. That made it illegal for the ships to operate highly lucrative casinos for virtually the entire time they were in Alaska.

Cruise industry lobbyists persuaded the legislature to change the law in 1994, but the governor at the time, Walter Hickel, vetoed the bill. The next year, the industry won a temporary exemption for a single season.

Frustrated in Juneau, the industry turned to Mr. Young, a former Yukon tugboat captain, asking him to assert federal authority over gambling within Alaska's waters.

He responded in the fall of 1996 by inserting an amendment into the Coast Guard authorization bill after public hearings had ended. The amendment, which applied solely to Alaska, prevented the state from banning gambling except when ships were docked or within three miles of a port of call. Mr. Young's staff acknowledged that the amendment had been sought by the industry and applied just to the big ships in southeast Alaska.

The change caught state officials by surprise. "All of a sudden came this federal law saying they could gamble," said Deborah Vogt, who at the time was the deputy commissioner of the state revenue department.

Meanwhile, Senator Murkowski was undoing plans to allow the National Park Service to weigh new antipollution standards for cruise ships in exchange for permitting more vessels to enter Glacier Bay, the national park and preserve 65 miles northwest of Juneau.

Glacier Bay is a 3.2 million-acre expanse of towering mountains, deep fjords and forests. It is home to abundant wildlife, including several species of whales, seals and otters, and its unspoiled beauty makes it the destination of choice for cruise ships.

For years, Mr. Murkowski had pushed to allow more ships into the bay, arguing that it was the most environmentally sound way for people to see the park. Park service officials resisted, fearing that the noise and air pollution would be harmful, especially to the endangered humpback whales.

After the Republican Party took control of Congress in 1994, Mr. Murkowski became chairman of the Energy and Natural Resources Committee, which oversees the budget of the Interior Department and the park service.

At Mr. Murkowski's urging, Interior Secretary Bruce Babbitt directed the park service to expand cruise ship permits to 184, or two ships a day, from about 100, during the three-month summer cruise season.

After environmental groups threatened to sue, a compromise was reached. A slightly slower expansion was approved on the condition that the park service receive authority to impose higher antipollution standards if they were found to be warranted by later studies.

"The amazing thing was that we managed to put together a plan that satisfied just about everybody," said Chip Dennerlein, the Alaska regional director for the National Parks and Conservation Association.

After the compromise was published in The Federal Register, however, Mr. Murkowski added a last-minute amendment to the 1996 parks bill that took away the park service's authority to increase pollution controls.

The change came at the urging of the cruise industry, whose lobbyists had argued that it was unfair to hold their ships to a higher standard than other vessels, according to Mr. Murkowski's staff and a former industry lobbyist.

"It was like the rug was pulled out from under us," Mr. Dennerlein said.

The park service was surprised, too. Robert D. Barbee, the regional director for Alaska, wrote to the cruise lines in March 1997 that the change "effectively negates a key mitigation measure" and that it prevented the park service from adopting "higher planning and operating standards."

Mr. Murkowski's chief of staff, David Garman, defended the senator's action, arguing that Glacier Bay could handle two ships a day without damaging the environment and that the park service should not establish antipollution standards. Mr. Garman also said the senator would consider tightening laws and regulations if it became clear that ships were polluting Alaska's waters.

The prospect of tightening regulations will be the subject of the coming public meeting in Juneau. The Alaska Department of Environmental Conservation scheduled the session after concerns were raised that current laws were no longer sufficient in this age of megaships.

"These ships are floating cities, really larger than most cities in Alaska," said Michele Brown, commissioner of the department. "But unlike cities, they don't need a permit to pump their waste into the Inside Passage."

With 3,000 or more passengers and crew members, a big cruise ship generates an average of 170,000 gallons a day of gray water from showers, sinks and dishwashers, and 17,000 gallons of black water, or human waste, according to industry officials.

Under current federal and international laws, ships can discharge gray water anywhere. Human waste and ground food waste can be discharged legally anywhere beyond three miles from shore.

The three-mile-limit standard has caused concerns in southeast Alaska because of the doughnut holes within the Inside Passage. Though technically international waters, the holes lie within the passage and adjacent to fertile fishing grounds and feeding areas for humpback whales. In October, The Anchorage Daily News reported that some ships had discharged waste in the holes.

Pointing to the holes on a nautical chart in his Juneau office earlier this month, Steven A. Torok, the senior Environmental Protection Agency official in Alaska, said the law did not take them into account. "Three miles offshore was intended to be three miles offshore, not within the Inside Passage," he said.

Two independent pilots who help ship captains navigate the passage said in interviews that they were often asked to take ships to the areas to pump waste water overboard.

"They say it's legal, but nobody's monitoring what's in that water," said Capt. Robert W. Smith, who has spent 50 years in Alaska's waters and said he had often been directed to the doughnut holes. "We live here and we want to know what they're dumping."

Capt. Ted Kellogg said he sometimes encountered so many ships discharging in the holes along the eight miles of Chatham Strait that he was concerned about safety. "They want to get to the middle of the strait to dump, and you'll have vessels meeting on reciprocal courses," he said.

Captain Smith and Captain Kellogg said most lines, including Celebrity Cruises, Holland America Line and Princess Cruises, dumped waste into the holes.

Julie Benson, a spokeswoman for Princess Cruises, said the company was declining to answer questions because officials thought previous articles in The New York Times about the industry had been unfair.

Erik Elvejord, a spokesman for Holland America, said the company's ships did not discharge waste water into the doughnut holes and never discharged raw sewage. Instead, he said, the ships treat their sewage on board and discharge legally permissible gray water only while traveling between ports so the waste mixes with the largest amount of outside water possible.

Holland America sends the most ships into Glacier Bay, and Mr. Elvejord said company policy did not allow even gray water to be discharged within the bay.

Nancy J. Wheatley, senior vice president for safety and environment at Royal Caribbean, which is also the parent company of Celebrity Cruises, said Celebrity ships might have used the doughnut holes to discharge waste on occasion. But, she said, no ships from either line ever discharge raw sewage within the Inside Passage, and both lines try to discharge as little gray water as possible.

"Our company goal is to discharge to the greatest extent possible outside of 12 nautical miles," Ms. Wheatley said.

Since pleading guilty twice in the last 18 months to criminal charges involving a fleetwide conspiracy to discharge oily waste water and hazardous material, Royal Caribbean has adopted voluntary standards to operate above legal requirements for discharges. It has also begun experimenting with treating gray water before it is discharged. The company's president, Jack Williams, said at a town meeting in Juneau last August that he thought the laws governing discharges should be more stringent.

No ship can store all of its gray water during the average seven-day cruise through the Inside Passage. As a result, it must be discharged. Though the lines say their ships do not discharge gray water while sitting in port and never discharge raw sewage in the Inside Passage, some regulators are skeptical.

"The cruise lines say that they don't discharge raw sewage, but the issue is that the law allows them to do it and this is a very competitive industry," said Mr. Torok of the Environmental Protection Agency. "The laws and regulations are outdated."

Ms. Brown, the Alaska environment commissioner, said she would not hesitate to ask Congress for new laws restricting discharges if regulators determined that such legislation was necessary.

In the meantime, the state of Alaska took the unusual step Friday of filing a lawsuit in the United States Supreme Court claiming jurisdiction over the waters of southeast Alaska, including Glacier Bay. The suit argued that the federal Submerged Lands Act gives the state the right to regulate activities in the waters, including discharges by cruise ships.