The United States is examining its "declaratory policy" on the use of nuclear arms under President Joe Biden's commitment to seeking to reduce the role of such weaponry, the State Department's top arms control official Bonnie Jenkins said recently.

Her remarks came as focus is increasing on whether the Biden administration will declare the "sole purpose" of U.S. nuclear forces is to deter or respond to nuclear attacks in its upcoming nuclear posture review, a guideline for American nuclear policy for the coming years.

U.S. President Joe Biden. (Getty/Kyodo)

But any moves that can be seen as reducing the current ambiguity in U.S. nuclear policy may raise concerns among allies that rely on American nuclear force for protection and prefer the vagueness as a way to complicate the calculations of adversaries.

"The nuclear posture review is examining the role of nuclear weapons in our overall national security and defense strategies. This includes declaratory policy," the undersecretary of state for arms control and international security said in a recent written interview with Kyodo News.

While noting it is premature to speculate on the outcome of the review, she said Biden has "committed to take steps to reduce the role of nuclear weapons in our national security strategy" and at the same time seeks to ensure that "our extended deterrence commitments to allies like Japan remain strong and credible."

The interview was the first Jenkins gave to a Japanese media outlet since assuming her current post in July. The U.N. conference on the Nuclear Non-Proliferation Treaty is also approaching in January.

The U.S. nuclear declaratory policy has so far centered on what is known as "strategic ambiguity" regarding the exact circumstances that might lead to a nuclear response, though efforts have been seen in the past to offer clarification.

Former President Barack Obama, who pledged in 2009 to pursue a world free of nuclear weapons, considered adopting a "no first use" policy, which would mean limiting the U.S. use of nuclear weapons only in response to nuclear attacks on itself or allies.

But his administration gave up the idea in the face of objections from some allies including Japan.

The Financial Times reported early this month that U.S. officials have reassured allies in Europe and Asia that Biden, who was vice president during the Obama administration, will not adopt a "no first use" policy. The officials will provide the president with options for a "sole purpose" declaratory policy, the newspaper said.

The sole purpose posture could leave open the possibility of using nuclear weapons first, if it were the only way to preempt an imminent nuclear attack by a country such as North Korea, pundits say.

Still, it could demonstrate a more restrained approach toward the use of U.S. nuclear weapons compared with the 2018 nuclear posture review compiled under Biden's predecessor Donald Trump. Under the former leader, the possibility remained nuclear weapons could be used not only against nuclear attacks but against "significant" non-nuclear attacks.

Bonnie Jenkins. (Photo courtesy of U.S. State Department)(Kyodo)

Jenkins said the views of U.S. allies are "incredibly important," and that Washington will continue to consult with them as it seeks to finalize its own review.

Meanwhile, she reiterated U.S. opposition to a U.N. treaty banning nuclear weapons, saying it will "not be an effective tool for nuclear disarmament" as nuclear powers have no intention to support it.

"The treaty will not result in the elimination of a single nuclear weapon. Instead, it will create political pressures that could undermine extended nuclear deterrence and U.S. security relationships with key allies all over the world," the official said.

The Treaty on the Prohibition of Nuclear Weapons came into force in January this year at a time when renewed attention was being paid to the catastrophic humanitarian consequences of any use of nuclear weapons. It only binds states that have formally signed and ratified it.

Jenkins also indicated Washington's desire to work with Japan toward a "common goal of a world without nuclear weapons," saying it respects the "special leadership role" Japan has, apparently referring to the fact the Asian nation is the world's sole country to have suffered nuclear attacks.

The U.S. atomic bombing of the Japanese cities of Hiroshima and Nagasaki in the final days of World War II "opened our eyes to the truth that a nuclear war must never be fought," the official said, hailing the role of atomic bomb survivors who have conveyed through their personal stories "the costs of the use of nuclear weapons."

But she said both Japan and the United States "must balance the desire to advance nuclear disarmament with the need to maintain nuclear deterrence."

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