According to multiple reports, President Joe Biden is abandoning a campaign pledge to change long-standing US nuclear doctrine and will instead embrace existing policy that reserves America’s right to use nukes in a first-strike scenario.

As Russian forces continue their bloody assault on Ukraine, Biden is under pressure from NATO allies not to give up the option of using nuclear weapons to deter conventional attacks.

Since the Cold War, American policy has permitted the use of nuclear weapons as a first strike in ‘extreme circumstances,’ such as responding to a conventional invasion or chemical or biological attacks.

However, during his campaign, Biden pledged to switch to a’sole purpose’ doctrine, which states that the US would only use nuclear weapons in response to another nation’s nuclear attack.

Instead, according to US officials, Biden’s recent Nuclear Posture Review reaffirms that nuclear deterrence is the ‘fundamental role’ of the nuclear arsenal, rather than the’sole purpose.’

Though the difference in wording may appear minor, Biden’s proposed “sole purpose” doctrine alarmed allies from Europe to Japan, who were concerned that the shift in posture would embolden adversaries.

Given Vladimir Putin’s recent moves against Ukraine, NATO allies were concerned that a policy shift would encourage Russia to launch new conventional attacks or use chemical weapons, knowing that a nuclear response from the US was out of the question.

According to the Arms Control Association, Russia currently has the world’s largest nuclear arsenal, with 6,257 warheads to America’s 5,550.

Instead of the’sole purpose’ doctrine, the new Nuclear Posture Review states that the US would only use nuclear weapons in ‘extreme circumstances,’ which is consistent with previous reviews conducted by both the Obama and Trump administrations.

According to one insider, Biden decided to abandon his’sole purpose’ pledge specifically after Russia invaded Ukraine.