'Fantasy' to expect US to go back to playing by the rules - expert

New Zealand must rethink its foreign policy towards the United States, an international relations professor says, after the replacement for "the most important role in the White House" was announced.

Stephen Miller, a longtime aide to President Donald Trump, has replaced Susie Wiles as the new White House chief of staff.

"It's probably the most important role in the White House," said Robert Patman, a professor of international relations at the University of Otago.

Patman said the chief of staff would be the closest person to the president in organisational terms.

He said Miller's appointment showed Trump was "doubling down" after the Republican midterm losses this week, during which Democrats rode a wave of support to take control of both chambers of Congress.

"I think if people were hoping that Trump would take note of the midterm elections and begin to moderate some of his policies, they will be disappointed by this appointment."

Patman said the midterm elections showed a lack of popular support for Trump's tariffs and immigration policies, which Miller had defended and helped develop - including the Immigration and Customs Enforcement (ICE) arrest targets.

"I think it does point to the need for New Zealand to rethink its foreign policy towards the second Trump administration. Because this administration, and in particular Miller, and Trump, neither of them believe in a rules-based international order, which has been the crucial vision of all New Zealand governments going back to 1945."

Patman said attempts to appease Trump in the hopes of better deals for New Zealand and of moderating the impacts of his policies had not worked.

"And in addition, we certainly have not been spared the economic consequences of Trump's Middle East military adventurism. The economic consequences have been significant."

Instead, Patman suggested cultivating ties with "alternative middle powers, such as Australia, Japan, Singapore, which is about the same size as New Zealand in terms of population, and many European powers".

He said New Zealand should seek cooperation with the US when interests overlapped.

"But where our interests diverge, such as Trump's attacks on the World Trade Organization, its attacks on the International Criminal Court, its aggressive use of tariffs and its threats, illegal threats against other countries, we have to stand very firm because after all, one of the lessons of the last two years is that keeping quiet does not actually protect you from the consequences of Trump's policies."

Patman said it was a "fantasy" to believe the US would return to its traditional role as "leader of the free world".

"Trump has contempt for many of America's liberal allies. And we have to face up to the fact that with Miller as chief of staff, Trump's more assertive instincts are probably going to prevail in foreign policy for the remaining two years of his administration."