THE REPUBLIC OF THE MARSHALL ISLANDS — A boy and his grandfather are fishing in the shallows off their tiny island, a dot of green in the sapphire eternity between Hawaii and Australia. The flash comes first, silent and brighter than the sun, from a four-mile-wide fireball beyond the horizon. The sky turns blood red. Wind and thunder follow.

Even 61 years after, Tony deBrum gets "chicken skin" when sharing his memories of the largest American nuclear-weapons test - the biblical, 15-megaton detonation on Bikini Atoll, 280 miles northwest of his island. Its flash was also seen from Okinawa, 2,600 miles away. Its radioactive fallout was later detected in cattle in Tennessee.

"We pause today to remember the victims of the nuclear-weapons testing program," deBrum says to a couple hundred people seated in a convention hall in Majuro, the capital of the Marshall Islands, a little-known nation that was entrusted to the United States as a primitive society 68 years ago.

It's March 2, Nuclear Victims Remembrance Day, and the boy in the shallows is now the foreign minister of the Marshall Islands, which has entered the 21st century as part trust-fund baby, part welfare state. Its elders have endured burns that reached to the bone, forced relocation, nightmarish birth defects, cancers in the short and long term. Its young people have inherited a world unmade, remade and then virtually forgotten by Washington, D.C.

The victims of the tests "have been taken from us before their time," deBrum says, so that Americans could learn more about the "effects of such evil and unnecessary devices."

From 1946 to 1958, the United States conducted 67 tests in the Marshall Islands. If their combined explosive power was parceled evenly over that 12-year period, it would equal 1.6 Hiroshima-size explosions per day.

This is not something one gets over quickly.

- - -

"Washington - and this is just my personal opinion - I think they're going out of their way to wash their hands of the Marshalls," says Jack Niedenthal, a Pennsylvanian who arrived in the islands with the Peace Corps in 1981 and eventually became one of their unofficial representatives to the United States. "You look at what they spend on Iraq and Afghanistan, and it's billions upon billions. For four bullets into a tree in Iraq, they could fix this entire place."

A woman peeks inside Niedenthal's office at the Bikini Atoll town hall, her face met by chilled air. Niedenthal is at his desk, toothpick in his teeth. He beckons her. She shuffles in, baby on hip, and says, "Where's my check?"

Niedenthal flips through paperwork, plucks out a slip of paper worth $147 and hands it over. This is the quarterly compensation for displaced Bikinians and their descendants. Splayed over Niedenthal's desk are checks for some of the 5,258 people who receive money from a trust fund administered by a division of M&T Bank in Baltimore. It's payday at town hall, a teal-colored building in Majuro, where Niedenthal - "Bikini Jack," as he answers his phone - manages the U.S. trusts that were capitalized as a kind of apology.

Majuro, home to the majority of the Marshallese population, is a town of 19,000 on a 30-mile ribbon of land that's never more than 2,000 feet wide. In almost every corner of Majuro you can hear or see the ocean or the lagoon. You can feel the isolation in the U.S. dollar bills, soft and faded from recirculation. You can see its commercial importance in the lagoon, where tuna ships and cold-storage freighters drop anchor.

When the local yacht club packs a bar for its weekly roustabout, Majuro feels like Margaritaville, with boisterous New Zealanders, Australians and Americans telling tales of the high seas. They dream of snorkeling in a 15-megaton crater. They recall elderly Marshallese who've interrupted their travels with comments like, "You Americans have ruined our country."

A half-mile from Bikini Jack's office is the village of Jenrok, where a couple thousand people are squeezed into 16 acres of tin-roofed shanties that aren't uniformly connected to public utilities, above groundwater that's contaminated by bodies decomposing in family graves.

The RMI, as the republic is called, is both vast and slight. There are 1,200 islands - spread out over a chunk of ocean the size of Mexico - whose combined land area is roughly equivalent to D.C.'s. American arrogance and American generosity collide here, and paradox reigns. It was once called the most contaminated place on Earth, yet it has the dizzy beauty of a mirage. Wealthy foreigners spirit themselves to surfer paradise, past islanders living with sky-high rates of diabetes and thyroid abnormalities. In a place where the United States has sunk billions, children play in landfills. The Marshallese couldn't exist without the ocean, but now sea-level rise attributed to global warming imperils their homes and lives.

Seven thousand miles away is Washington, its tough-love parent, delivering an annual allowance for the RMI's operations while trying to close the book on a history of destruction and sadness. The United States has been an epic force here for 70 years, and decisions made over the next decade could save the islands or seal their fate.

- - -

On a Sunday after church in 1946, a Navy commodore met with the people of Bikini Atoll and told them they were like the Israelites, a chosen people, and that perfecting the atomic bomb would deliver mankind from future wars. Within one month of that conversation, the Bikinians had boarded U.S. ships for relocation. Within five, the first two tests had been conducted.

"We located the one spot on Earth that hadn't been touched by the war and blew it to hell," Bob Hope reportedly once said.

In 1954, the "Castle Bravo" test, the one deBrum talks about, detonated with 1,000 times the force of the Hiroshima explosion. It hurled into the sky a massive plume of pulverized coral that drifted eastward and fell like ashy snowflakes on the people of Rongelap and Utirik atolls. Several days after Bravo, after children had eaten the ash, American servicemen and several hundred Marshallese residents were evacuated from Rongelap and Utirik.

The following month, the Marshallese filed a complaint with the United Nations, which after World War II had conveyed the islands to the United States as a "trust territory."

"Land means a great deal to the Marshallese," the complaint said, adding, "Take away their land and their spirits go also."

The United States, which had pledged to usher the islands to self-determination, replied that "no stone will be left unturned to safeguard the present and future well-being of the Islanders."

Fifty-four tests followed on Bikini and another atoll, named Enewetak. The U.S. government viewed the 1957 resettlement of Rongelap as an opportunity to study subjects who, while uncivilized, were "more like us than mice," as the Marshallese were described in a meeting of the Atomic Energy Commission. Many more tests, at much smaller yields, continued stateside in Nevada, with American "downwinders" enduring their own sagas of government deception and failing health.

The years since 1958, when testing ended in the Marshalls, have been fraught with contentious science, legal battles, false starts and halfway resolutions. Bikini and Rongelap atolls were resettled and then re-evacuated because of lingering contamination. As part of a "compact of free association" in 1986, the United States granted the Marshall Islands its independence and a "full and final" cash settlement of $150 million - which included individual trust funds for the test atolls, Bikini and Enewetak, and the fallout atolls, Rongelap and Utirik.

In 2001, an independent nuclear-claims tribunal awarded the RMI $2.3 billion in health and property damages, but there was no mechanism to force the United States to pay it. Washington does not consider itself liable beyond the original settlement and points to the additional tens of millions of dollars it grants every year to environmental, food and health-care programs.

The problem? These sector grants are decreasing yearly until 2023, when they expire. Plenty of treasure has already been lost in the clumsy merger between a Western economy of cold hard cash and a feudalistic society in which traditional chiefs and landowners hold sway.

What Americans consider welfare, the Marshallese consider normal historical function: Fish, coconuts and other perishables were given to the chief to distribute promptly and fairly, to avoid waste and to keep the peace. Then America, with its deep pockets, became the de facto high chief.

Now, a new trust fund is being capitalized by the United States at a rate of $12 million to $16 million a year to provide a life jacket for the RMI economy after 2023. But this fund would be just as vulnerable to hasty distribution as existing trusts, which have been siphoned at times by the Marshallese.

"I think the U.S. acquitted itself reasonably," says a U.S. policy adviser on the Marshall Islands who requested anonymity because he is not authorized to speak for the federal government. "We did a horrible thing, but we provided compensation, and then a lot more."

The Marshallese culture is rooted in a history of resource sharing, ecological balance, of an intimate knowledge of how the winds blow, how the waves break, how the stars slip across the sky. Over the past 70 years, though, victimhood, corruption and dependency have produced a different kind of fallout.

"We have basically destroyed a culture," says Glenn Alcalay, an anthropology professor at New Jersey's Montclair State University who took part in Greenpeace's second evacuation of Rongelap in 1985. "We've stolen their future. When you take the future from a people, you've destroyed them."

- - -

The future of the Marshall Islands is dressed in blue jumpers and seated in pews at the Cathedral of the Assumption in central Majuro. Sixth-graders at the adjoining school take turns at the pulpit, below a projection screen showing images of burned children and deformed babies.

"We are made in God's image, and no one has the right to take our life."

"Castle Bravo is an example of arrogance."

"We are all victims."

After this commemoration service, the students scamper outdoors to set up display tables for their annual nuclear science fair, held the Friday before Nuclear Victims Remembrance Day.

Sophomore Limbuk Ackley, whose mother is Marshallese and father is American, stands near a heap of peace cranes. "It's hard to take in what my mom's ancestors had gone through and what my dad's ancestors had done to inflict problems," says Limbuk, 16, as students run around in the muggy heat.

There are no permanent oncologists in the RMI, no ability to administer cancer treatments such as chemotherapy, and no true consensus between the U.S. Energy Department and the Marshallese about the effects of exposure, during or after the tests.

There's no health risk to the current generation of inhabitants from radioactive contamination, according to a 1994 study commissioned - and then rejected upon completion - by the RMI government. But cancer and birth defects are the modern connections to the past. There are still radiation-related cancers that have yet to develop or be diagnosed in the population of Marshallese who were on the islands between 1948 and 1970, according to a 2004 report by the U.S. National Cancer Institute. Everyone seems to have a relative whose cancer falls on the Energy Department's list of ailments traceable to radiation.

In many ways the cultural fallout is more insidious. Some Marshallese are either nervous to marry people from the exposed atolls, for fear of passing genetic mutations to offspring, or keen to do so, because it means tapping into trusts. There is tension between residents of the trust-fund atolls and the rest of the islanders, who view the United States as delinquent on a $2 billion IOU from the claims tribunal.

The other 364 days of the year, young Marshallese confront problems more emergent than the past: rampant alcohol abuse, schools that don't provide lunches, and an ongoing suicide epidemic. U.S food aid comes in the form of processed items such as chicken and white rice, which have contributed to an epidemic of obesity and diabetes - the No. 1 cause of death here (cancer is No. 2), according to a report from the U.N. Human Rights Council.

"The Marshallese are convinced that there is sufficient evidence - based on their own observations of changes to their reproductive functions - of intergenerational harm caused by radiation fallout," said the report, which also noted "a deep fissure" between the U.S. and RMI governments.

The major perk of the compact with the United States allows Marshallese citizens to work indefinitely in the United States without a visa, and the most promising students often emigrate - or enlist in the U.S. military - and rarely return. They settle in Hawaii, on the West Coast or in northwest Arkansas, where Marshallese expats represent up to 38 percent of the workforce at major poultry producers such as Tyson Foods.

Students afford college here through Pell grants, which are available through the relationship with the United States. The Pell eligibility expires in 2023, and there is growing anxiety about what will happen afterward to higher education in the Marshalls.

But at least one major agreement between the countries will endure: the U.S. military's lease of a handful of islands in the northern Kwajalein Atoll, where the Army still operates a missile test range.

- - -

Kwajalein was known as "Execution Island" during World War II, when the Japanese used it as a POW camp. Louie Zamperini, the subject of the book and film "Unbroken," was held there for 42 days and tortured. Today, the U.S. dining facility is named after him.

The garrison is referred to as "Kwaj." It's just over 2,100 miles west-southwest of Hawaii. About 1,300 American service members, contractors, civilians, scientists and families members live there in bungalows and two-story barracks. There's a golf course and a yacht club. It's a bike-or-walk community - "boring as hell," as one contractor describes it, but not unpleasant. Kwajalein Atoll surrounds the biggest lagoon in the world, and because of its remote location and its foothold in the Pacific, it is perfect for target practice.

The atoll is a key location for American missile activity. When an unarmed intercontinental ballistic missile is launched from Vandenberg Air Force Base in California, 4,278 miles away, it sometimes plunks down near Kwajalein. Such a missile could carry a nuclear warhead that would deliver 20 times the payload of Hiroshima. Sometimes a test missile is launched from Kwaj toward California and intercepted by another missile from Vandenberg. With Kwaj, the United States can practice launching or deflecting nuclear attacks, provide a territorial bulwark against China, immediately detect any launch out of Asia (read: North Korea) and provide a rocket-launch apparatus to civilian companies such as SpaceX.

"Remote Pacific location is ideal for permissive safety and environmental constraints," says one pamphlet for the Ronald Reagan Ballistic Missile Defense Test Site.

Though the garrison has been downsizing since the 1980s, the Defense Department's lease does not expire until 2066. The rent ($15 million per year) goes to a small group of landowning Marshallese families who live abroad. About 900 Marshallese work on Kwaj - flipping burgers, groundskeeping, working in the carpentry or electrical shops - but they live a 20-minute ferry ride away, on a squalid sliver of land called Ebeye.

More than 10,000 people are crammed into a tenth of a square mile of livable space on Ebeye. The island is crawling with children. A third of its residents are unemployed and over half are under 20 years old. Government buildings stand on crumbling stilts with exposed rebar, the concrete spalled away by a constant salty wind off the ocean. Raw sewage pools in the streets. There are occasional outbreaks of cholera and dengue fever. The hospital has an on-again-off-again insect problem.

Ebeye, which is also a Rongelap resettlement, has been known as "the slum of the Pacific" for decades. But people live here for the country's highest hourly wage: Workers at the U.S. garrison make $10 to $12 an hour. The minimum wage in Majuro is $2 an hour.

Decent pay in lousy conditions is more appealing than living on remote Rongelap, which some islanders still fear is contaminated, even though the Energy Department has approved resettlement and the Interior Department has paved roads and built homes.

"We'd have better living conditions in Rongelap," says Kenneth Kedi, one of that atoll's senators, "but what is underneath the houses, the grass, the pandanus, the papaya, the coconut trees? . . . As a leader, I'm caught between here and there. I want to go back to Rongelap now, but at the same time I'm not going to bring my family, especially the young children."

- - -

Tony deBrum and microphones are a natural pair.

"I wonder how many in this room have actually witnessed a detonation of a nuclear weapon," he said to 191 delegations in the U.N. General Assembly hall in late April, on the first day of a conference on the Nuclear Non-Proliferation Treaty.

He paused a moment, waiting for a show of hands that he knew wasn't coming.

"I have," he continued. The Marshallese "still carry a burden which no other people or nation should ever have to bear."

DeBrum then railed against nations that are modernizing their arsenals, a trend that he and other nations say is a violation of the grand bargain of the treaty: that states refrain from obtaining such weapons if the United States and others negotiated the elimination of their stockpiles. The United States is extending the life of its warheads, shrinking but updating its weapons infrastructure, and planning to construct a new fleet of submarines with nuclear-armed missiles.

The price tag on this modernization plan? One trillion dollars over the next 30 years, according to the James Martin Center for Nonproliferation Studies. Even though the United States has reduced its stockpile by 86 percent from its Cold War high, this reinvestment in nuclear arms doesn't sit well with a poor island nation that has actually felt what nuclear war would be like.

Last year the RMI filed lawsuits against the United States and the eight other nuclear-armed nations, alleging noncompliance with the Non-Proliferation Treaty. The news caught most Marshallese, including RMI officials, by surprise. The Nuclear Age Peace Foundation in California engineered the lawsuits in collaboration with deBrum, who has been their cheerleader. The suits were filed in U.S. District Court in San Francisco and to the International Court of Justice.

The U.S. Justice Department, in its motion to dismiss, implied that the lawsuit is a stunt that has no business in the court system. A federal judge in San Francisco dismissed the suit in February (the RMI appealed), and it's a nonissue in the international court, since the U.S. government does not recognize that court's jurisdiction.

No matter, deBrum says. It's the principle of the thing, particularly in this year of the 70th anniversaries of Hiroshima and Nagasaki, and with next year's 70th anniversary of the first atomic test in the Marshalls.

He comes to the country he's suing a couple of times a year, to preach about the connection he sees between a nuclear past and a climate-change future. Just 45 minutes away from Majuro by air, 500 Bikinians are struggling on Kili, a rocky island without a lagoon where their elders were exiled. A ship bearing food and diesel arrives every three months, if the weather behaves. In February, the yearly king tide washed completely over the island, fouling freshwater reservoirs.

DeBrum is lobbying Congress to amend U.S. law to definitively allow Bikinians to use their resettlement funds to relocate to the United States.

"How can you separate nuclear from climate with Bikini and Kili?" deBrum says during a reception last month in the Rayburn House Office Building, where anti-nuclear nonprofit groups gave him an award for his work. "It's the classic case of one meeting the other. You have nuclear refugees on an island affected by climate change."

- - -

"Nuclear issues are forever."

This is Tom Armbruster, the U.S. ambassador to the RMI since 2012. Outside his office window is a balcony with a peach-colored balustrade, beyond which the ocean laps over crushed coral on the outer edge of Majuro, where the average elevation is six feet.

"A lot of these people are living with those ghosts," says Armbruster, bald, lanky and considered by many Marshallese to be savvy and empathetic. "It's part of our shared history, part of our Cold War. We're not going to go back and try to understand the decisions. But there are things we can do now."

He lists them: encouraging the resettlement of Rongelap, sending a couple of Marshallese students to California to study nuclear issues, building drinking-water catchments, strengthening disaster management plans.

The U.S. Embassy considers the Marshall Islands to be on the front line of climate change, which manifests most dramatically during late-winter king tides. In March of last year, 1,000 people evacuated Majuro as the surge pulled homes into the ocean.

"Climate change is my nuclear experience," says Mark Stege, 37, who grew up in Majuro, studied at Columbia University and is now director of the Marshall Islands Conservation Society. "I can see a lot of connections at the emotional level, and the community level, at the individual family level. The same questions are relevant in both situations. There's this really deep sense of loss."

On the afternoon of Nuclear Victims Remembrance Day, Armbruster hosts the unveiling of a U.S.-funded memorial at an outdoor basketball court near the college. The court is named after Solomon Sam, the only Marshallese service member in the U.S. military to die in Iraq or Afghanistan. Painted in white text on a blue wall is a written tribute to the Marshallese who have served the United States in some form over the past 70 years: scouts who gathered intelligence during World War II, families whose land and health were poisoned by testing during the Cold War, and the young generation who served in the Middle East.

Most of the white plastic chairs at the unveiling are empty.

Present at the ceremony is a young Marshallese man who served in the U.S. Army and deployed to Baghdad. The young man, who is absent without leave from the Army and asked not to be identified, says he thinks the memorial is a fine gesture from the United States.

"We're biting the hands that feed us," he says of remarks critical of the United States made earlier that day. "We're sending out the message that this happened and we're supposed to be pissed, and that's been going on for 61 years. Why not change the tone? It's really depressing."

The young man was a combat engineer, with a focus on explosive-ordnance disposal. He helped protect American troops from bombs.

- - -

Over the rest of the year, nuclear issues would dominate the global stage. At the United Nations, the Non-Proliferation Treaty conference would break down over a proposed WMD-free zone in the Middle East. A month later in Vienna, the United States and its allies would negotiate a controversial deal with Iran to relieve sanctions while hampering an Iranian pursuit of the bomb. The State Department would step up its promotion of the Comprehensive Nuclear Test-Ban Treaty - which remains unratified by the U.S. Senate - even as tensions between Russia and NATO nations reached heights not seen since the Cold War. A bill would be introduced in Congress to provide for the treatment of American veterans who helped clean up Enewetak in the late 1970s.

Things would be quieter on Kwajalein Atoll. The U.S. garrison would host an inner-tube water-polo championship in Kwaj's family pool, and the Turbo Turtles would win the coveted coconut trophy.

Kwajalein High School would celebrate its 10th anniversary, though its campus would remain closed; the causeway that connects it to mainland Ebeye is so run-down that it's impassable by bus.

The Air Force would break ground across the lagoon on a six-acre "Space Fence" radar site. With pinpoint accuracy it will track bits of debris in orbit, miles above the planet, to safeguard satellites. It is expected to cost around $2 billion.

All of Ebeye would gather for the funeral of its mayor, who died of a heart attack around the anniversary of the Castle Bravo test.

And on May 20, Aug. 19, Oct. 21 and Nov. 9, the latest set of test missiles would launch from the California coast on short tails of white fire, bound for a familiar target.