New type of weapon, ordered by Trump’s nuclear posture review, could make conflict more likely, say experts

The US has begun making a new, low-yield nuclear warhead for its Trident missiles that arms control advocates warn could lower the threshold for a nuclear conflict.

The National Nuclear Security Administration (NNSA) announced in an email it had started manufacturing the weapon at its Pantex nuclear weapons plant in Texas, as ordered by Donald Trump’s nuclear posture review (NPR) last year.

The NNSA said the first of the new warheads had come off the production line and that it was on schedule to deliver the first batch – an unspecified number referred to as “initial operational capability” – before the end of September, according to the email, first sent in response to an enquiry from Exchange Monitor, which covers the nuclear weapons complex.

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The new weapon, the W76-2, is a modification of the existing Trident warhead. Stephen Young, a senior Washington representative of the Union of Concerned Scientists, said its yield had most likely been cut by taking away one stage from the original two-stage, W76 thermonuclear device.

“As best we can tell, the only requirement is to replace the existing secondary, or second stage, with a dummy version, which is what they do every time they test fly a missile,” Young said, adding that the amount of tritium, a hydrogen isotope, may also be adjusted. The result would be to reduce its explosive power from 100 kilotons of TNT, to about five – approximately a third of the force of the bomb dropped on Hiroshima.

The Trump administration has argued the development of a low-yield weapon would make nuclear war less likely, by giving the US a more flexible deterrent. It would counter any enemy (particularly Russian) perception that the US would balk at using its own fearsome arsenal in response to a limited nuclear attack because its missiles were all in the hundreds of kilotons range and “too big to use”, because they would cause untold civilian casualties.

Low-yield weapons “help ensure that potential adversaries perceive no possible advantage in limited nuclear escalation, making nuclear employment less likely”, the 2018 nuclear posture review said.

To what extent does this signal a new willingness on the part of the US to start using strategic nuclear weapons? Hans Kristensen, Federation of American Scientists

Many critics say that is an optimistic scenario that assumes there will be no miscalculation on the US side.

“There are many other scenarios, especially with a president who takes pride in his unpredictability and has literally asked: ‘Why can’t we use our nuclear weapons?’”, Young said.

Melissa Hanham of the One Earth Future foundation pointed out that adversaries would have no way of knowing if a full-force Trident was being fired at them, or its low-yield cousin.

“Hey all you nuclear powers out there. We’re just going to trust that you recognize this is “just a little nuclear weapon” and won’t retaliate with all you’ve got,” Hanham wrote in a tweet. “Remember! The US only intends to nuke you “a little bit.””

Hans Kristensen, the director of the nuclear information project at the Federation of American Scientists said the new warhead marked a sharp break from the Obama administration policy of making no new weapons or capabilities. He said it risked starting an arms race with Russia involving smaller nuclear weapons.

“To what extent does this signal a new willingness on the part of the US to start using strategic nuclear weapons in a tactical and very limited way early in a potential conflict?” Kristensen asked. “Frankly, mission creep is my greatest worry about this.”

There has been a spate of developments signalling that a new arms race is gathering pace. Vladimir Putin has unveiled a new generation of Russian weapons, and Russia’s suspected development of an cruise missile banned under the 1987 Intermediate-range Nuclear Forces (INF) treaty.

Trump has declared he will take the US out of the treaty, and the administration is expected to suspend compliance and serve six months’ notice of withdrawal on Saturday.

The Trump nuclear weapons review expanded an ambitious modernisation plan already underway. It ordered work to start on a new sea-launched cruise missile and blurred the line between the use of conventional and nuclear weapons.

The NPR said the US could respond with nuclear weapons against “significant non-nuclear strategic attacks,” including attacks on “civilian population or infrastructure”. It also said the US would “strengthen the integration of nuclear and non-nuclear military planning”.

It is not inevitable that all of Trump’s nuclear weapons plans will be pursued. Since the funds for the initial batch of warheads was approved, Democrats have taken over Congress, and are sceptical about their cost and purposes.

Last week, the non-partisan Congressional Budget Office issued a report projecting the nuclear weapons costs over the next decade as nearly a half trillion dollars, up 23% from the last estimate two years ago.

“I don’t think we need as many as they’re talking about,” Adam Smith, the new head of the House armed services committee, said in a C-Span interview. “I just don’t think we can afford what the NPR is calling for and I don’t think it is necessary.”

The nuclear weapons budget is likely to be an important battlefield in the struggle between Trump and congressional Democrats. The president is increasingly surrounding himself with Reagan-era nuclear hawks, including John Bolton, his national security adviser and who pushed for the INF to be jettisoned. Bolton’s new deputy, Charles Kupperman, once argued a nuclear war could be won “in the classical sense” if one side emerged the stronger, even if there were tens of millions of casualties.

Speaking to reporters last week, former defence secretary William Perry, an arms control advocate, said he was less worried about the number of nuclear warheads left in the world than by the return of cold war talk about such weapons being “usable”.

“The belief that there might be tactical advantage using nuclear weapons – which I haven’t heard that being openly discussed in the United States or in Russia for a good many years – is happening now in those countries which I think is extremely distressing,” Perry said.

“That’s a very dangerous belief.”