SAN FRANCISCO (CN) – The Ninth Circuit ruled Monday that the judiciary lacks the authority to order the United States to fulfill its international treaty obligations to eradicate nuclear weapons, sounding the death-knell for a three-year campaign by the Republic of the Marshall Islands to eliminate the weapons worldwide.

Affirming a lower court’s dismissal of the island nation’s lawsuit centered around Article VI of the Treaty on the Nonproliferation of Nuclear Weapons (NPT), a three-judge panel ruled in a scathing decision that the provision is not enforceable in U.S. courts and that the republic’s claims raised political questions beyond the courts’ jurisdiction.

“At bottom, the suit is doomed because diplomatic negotiations among parties to this treaty fall quintessentially within the realm of the executive, not the judiciary,” Circuit Judge M. Margaret McKeown wrote for the panel. “Asking the federal court to order the United States to negotiate in ‘good faith’ on ‘effective measures’ for nuclear disarmament puts the judiciary in the role of nanny to the executive.”

The Republic of the Marshall Islands sued the United States and eight other nuclear-armed nations in 2014, accusing them of violating the 1968 treaty by failing to dismantle their nuclear arsenals. It asked a federal judge to find the United States in breach of its treaty obligations and to order it to convene negotiations within one year to eliminate the weapons.

The treaty prevents non-nuclear nations from acquiring nuclear weapons, and requires nations with nuclear arms to negotiate their elimination. More than 180 states have signed the agreement.

The United States used the Marshall Islands, located halfway between Australia and Hawaii, as a testing ground for nuclear weapons during the first part of the Cold War, detonating 67 nuclear weapons there between 1946 and 1958. A 2016 study by Columbia University researchers found that radiation levels in some parts of the islands are two times higher than what is considered safe. One explosion was so devastating that some residents were permanently displaced.

U.S. District Judge Jeffery White dismissed the domestic suit against the United States in 2015, finding the Marshall Islands lacked standing under the Constitution.

White said the case raised political questions beyond his jurisdiction. Granting the republic’s requested relief – forcing the United States to negotiate with other nations in good faith – would violate the separation of powers because such a decision belongs to the executive branch, he said.

The Ninth Circuit agreed, ruling Monday that Article VI is non-self-executing, or not enforceable in a U.S. court, that the Marshall Islands’ asserted injuries are thus not redressable, and that its claims raise nonjusticiable political questions meant for the executive.

A self-executing treaty is judicially enforceable upon ratification, while a non-self-executing one usually requires Congress to pass implementing legislation, according to the panel’s 26-page opinion.

“Not all treaties are created equal in terms of enforceability,” McKeown wrote, concluding that Article VI does not direct domestic courts to enforce it, as required under the Supreme Court’s 2008 decision Medellín v. Texas.

McKeown explained that Article VI instead addresses the executive branch, “urging further steps only the executive can take – negotiation with other nations.” It also addresses the Senate, “because it calls for ‘a treaty on general and complete disarmament,’ which would, under the Constitution, require both the president’s signature and the Senate’s consent,” she wrote.

“A provision cannot be judicially enforced if doing so would compel the courts to assume a role constitutionally assigned to the executive or the Legislature,” McKeown wrote. “There is perhaps nothing more prototypically political than the negotiation of a multilateral international instrument. Deciding when, where, and whether to negotiate with foreign nations is within the exclusive authority of the executive.”

She added: “Granting the Marshall Islands’ requested relief would essentially appoint the district court as a special master overseeing the United States’ nuclear treaty negotiations. To construe Article VI as self-executing and approve the Marshall Islands’ claims would thus violate core separation-of-powers principles.”

Moreover, McKeown found, Article VI does not suggest that presidents Lyndon Johnson and Richard Nixon or the Senate intended the provision to be enforceable domestically. Although the treaty notes the “intention” of the parties to disarm, it is “silent as to any enforcement mechanism” if a country fails to comply with its obligations, the judge said.

“That silence is significant in the context of this treaty and this lawsuit, not least because, in the absence of a specific treaty directive, having states open their domestic courts to other treaty parties would be extraordinary,” McKeown wrote.

And, she added, Congress passed a law after the treaty was ratified conferring responsibility for the international negotiation of arms control and disarmament to the U.S. secretary of state.

Marshall Islands attorney Laurie Ashton of Keller Rohrback in Phoenix expressed disappointment with the decision Monday.

“With respect, the court’s decision purports to say that it is without authority to determine the nature and scope of the Article VI obligation, but then the court turns around and does just that, holding that Article VI, in its ‘wishful tenor reflects the reality of the treaty itself: the state parties could agree only that they hoped to usher in a nuclear-free future,’ Ashton wrote in an email.

“But if hope were all that were offered in Article VI, the NPT would have been … at risk of failure for lack of consideration. In other words, in exchange for the non-nuclear weapon states’ promise to not acquire or transfer nuclear weapons, the nuclear weapon states offered only “hope” under today’s decision,” she continued. “But that’s not a contract. The obligations of non-nuclear weapon states to not advance nuclear weapons programs are in the news at least weekly and often daily. It is not difficult for one to imagine the effects of the United States position, as held by the Ninth Circuit, that its Article VI obligation is hortatory, and reflects only its ‘hope.'”

The Justice Department declined to comment on the decision.

The Marshall Islands also sued the United States, along with the United Kingdom, Russia, France, China, Israel, India, Pakistan and North Korea, at the International Court of Justice in the Netherlands. That court ruled last October that it did not have jurisdiction to hear the merits of the cases against the United Kingdom, India and Pakistan.

The remaining nations ignored the cases against them because they do not recognize the court’s compulsory jurisdiction.

U.S. Circuit Judge Jay Bybee and U.S. District Judge Susan Oki Mollway, sitting by designation from the District of Hawaii, joined McKeown on the panel.

A representative for the Marshall Islands’ department of state could not be reached for comment.

Justice Department attorney Sushma Soni represented the government.