Donald Trump’s upending of the global order is likely to entrench permanent change, says a former top NATO official who is urging Western democracies including Australia to spend more on defence and work together to fill the void left by a United States in retreat.

Rose Gottemoeller also predicted Russian President Vladimir Putin could not afford to “diddle” Trump by holding out on a ceasefire deal in Ukraine, running the risk of the US tightening the economic screws further against Moscow.