For 22 years, the United States has been waiting for radioactivity to diminish on the Pacific atoll of Enewetak, where 43 nuclear devices were detonated between 1947 and 1958, so that the Marshallese natives can return to their traditional home.

And tomorrow, 175 Marshallese men, women and children will return by boat to Enewetak island to take up residence. Their home island has been made habitable by a three-year, $100 million cleanup.

They will return in the face of opposition, announced last week, to the resettlement by the newly elected president of the Marshall Islands government, Amata Kabua, who said in a letter to President Carter that he doubts the atoll is safe from harmful radation.

Kabua is the son of one of the Marshalls' hereditary chiefs and a fierce political opponent of the Enewetak people.

In turn, the Enewetak tribal chiefs, who have waited 33 years to return to their islands, responded with a letter to Carter.

Sent Friday, it said Kabua's motive in opposing resettlement of Enewetak is "money and politics" and not their welfare.

For President Carter, this tempest over resettlement is more than just a political and environmental issue -- it has national security overtones.

The United States is trying to complete its new relationship with the Marshalls to guarantee continued American access to its important missile testing facilities on Kwajalein, another of the Marshalls' atolls.

But to work out completion of the compact that was signed in January, the United States has to get Kabua's agreement -- not that of the Enewetak people.

Thus while the Enewetak people railed at Kabua's intervention, one U.S. official took up his cause.

The man caught in the middle of the Marshallese hardball politics game was Peter R. Rosenblatt, the U.S. ambassador who is attempting to complete negotiations with Kabua on the subsidiary agreements to the compact signed Jan. 14.

Rosenblatt heard of Kabua's objections to the Enewetak program and sent an internal government memo critical of excluding Kabua and his government from the Enewetak resettlement. Rosenblatt said Kabua's government "has a legitimate interest in the proceedings as spokesman for, and guardian of the interests of all of the people of the Marshall Islands."

He concluded by asking that the program "be put on ice."

While Rosenblatt's effort may have been diplomatically correct given his need to work with Kabua, it was not received well in Washington.

Most angered, according to sources, was Vice Adm. Robert R. Monroe, director of the Defense Nuclear Agency and driving force behind the enormous and costly cleanup program.

His claimed sucess in driving down the amount of residual radiation led the Enewetak people to ask for resettlement on some islands that once were considered impossible to make habitable.

In their letter to Carter, the Enewetak chief called Monroe "a kind and dear friend."

Several weeks ago, Monroe invited Kabua to join him in flying to the Enewetak ceremony to be held tomorrow -- an inviation Kabua reportedly acknowledged but refused, saying he wanted to go to Enewetak in his own boat.

Now, Kabua has told the Americans he is not going.

A White House source said Friday that President Carter will respond to Kabua's letter by saying the United States has worked closely with the Marshallese throughout the Enewetak cleanup and expects the resettlement to take place without delay.

The flurry over resettlement may just be the first of many tensions to arise in the new U.S. relationship with the Marshalls.

Although the islands voted to replace the U.S. trusteeship that has existed since World War II with "free asssociation," the atolls affected by American nuclear testing -- Enewetak, Bikini, Rongelap and Utirik -- were not those favoring the new status.

Each atoll has looked to Congress over the years for money and programs to make up for the health problems that stemmed from exposure to radiation from the U.S. atomic testing and for the loss of their lands.

They make it clear to interviewers that they don't want the programs funneled through Kabua.

The Enewetak chiefs said in their letter to Carter: "We know President Kabua very well and we do not trust him."

Under Marshallese custom the chief is entitled to any gratuities given his people. When the Rongelap people were compensated in 1963 for fallout from an American hydrogen bomb test, Kabua arranged for the $11,000 per person payment to be made in cash, though the islanders didn't understand the use of money.

At the presentation cerermony, Kabua's father was handed $1,000 by most of the recipients as the customary tribute given the chief. Kabua himself sold many of the Rongelapese motorboats and trucks and got some to invest in his trading company, which later failed.

Later, in 1972, when a Marshallese company was given the contract to build homes for the Bikinians so they could return to their home island, Kabua was part-owner of the company.

One U.S. official who has dealt extensively with Kabua acknowledged his "merchant prince" activities in the past but added, "I think he has changed. He seems to be more responsible as leader of all the Marshall Islands."

The Enewetak people, however, do not share that view.

Over the next several years, and perhaps longer, they are to receive U.S. food shipments to tide them over until the newly planted coconuts and other fruit trees begin to produce.

They say they do not want those shipments controlled by Kabua.

"He has never done anything in his entire life to help us," the Enewetak chiefs wrote Carter, "and we reject his false claim to be our friend now."