At a campaign speech in an American Legion hall in New Hampshire last week, Nikki Haley animatedly warned the US must prepare for a war with China. Haley, the former ambassador to the UN under President Donald Trump, rattled off the size of the Chinese navy, warned of China's advances in artificial intelligence and hypersonic missiles, and worried about the development of "neurostrike" weapons that can scramble the brains of military commanders in the field.

China has been preparing for war with the US for years, Haley told the crowd of about 100 people gathered on an icy night in Rochester. It needed to be treated like an "enemy", not a "competitor," and the US was not ready, she said.

"We've barely gotten started," she said.

Trump, who leads Haley in the Republican presidential nominating battle, has taken an entirely different tack in New Hampshire, which holds its primary on Tuesday. At rallies across the state, he tells voters that he alone can keep the nation out of “World War Three” and defends his relationships with some of the world’s most authoritarian rulers, including China’s Xi Jinping.

With just two candidates left in the Republican race, the New Hampshire vote pits the most hawkish in Haley against the more isolationist Trump, who would rather avoid foreign entanglements in keeping with an "America First" approach. Trump is favoured to win the primary, while Haley is hoping to draw enough support to argue that she is a viable threat to Trump going forward. The nominee will face President Joe Biden, a Democrat, in the November 5 general election. Foreign policy normally does not assume a large role in US presidential elections, where domestic concerns are at the forefront of voters' minds. But with the war in Ukraine still raging, Israel battling Hamas in Gaza, and China signalling a more aggressive posture in Asia, these are not normal times.

“The world is on fire,” Haley likes to say at her events.