US President Joe Biden will have to walk a fine strategic line when he unveils his administration's nuclear policy.
The policy, known as the nuclear posture review, is expected to be released this month and will have to balance the two competing aims of restraint and firm defence amid worsening relations with China and Russia.
On the one hand, Biden ran for office on a commitment to ensure that the "sole purpose" of the US' nuclear arsenal "should be deterring - and if necessary, retaliating against - a nuclear attack".
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And in March, in its interim national security strategic guidance the administration said: "We will take steps to reduce the role of nuclear weapons in our national security strategy."
But there is huge domestic opposition to this pledge, according to Zhao Tong, a senior fellow in the nuclear policy programme at the Carnegie Endowment for International Peace in Beijing.
"Many opponents believe that while Russia, China, North Korea and other countries are actively developing nuclear forces, the United States has no reason to impose further restrictions on its nuclear policy," Zhao said.
He said there was also pressure from US allies who feared a US nuclear policy of self-restraint would encourage military expansion of hostile countries.
When the review is released, it will be the fourth such document from a US administration since 1994.
As well as setting out a general nuclear weapons policy, it is expected to contain a reassessment of the number, kind, and purpose of the warheads.
The review has been months in the making and the Financial Times reported in October that US allies, including Britain, France, Germany, Japan, and Australia, were lobbying Biden not to commit to a "no first use" policy, arguing that doing so would weaken deterrence against China and Russia.
There is also debate on whether Biden will cut the numbers of nuclear weapons. In December, nearly 700 scientists and engineers, including 21 Nobel laureates, asked Biden to use the review as a chance to cut the US arsenal by a third, and to declare, for the first time, that the United States would never be the first to use nuclear weapons in a conflict.
The US has shown signs of leaning towards restraint, joining China and three other nuclear-armed countries last week in pledging to use nuclear weapons only for defensive purposes.