Washington | A partial rebound in third-quarter economic growth late on Thursday (AEDT) will give Donald Trump bragging rights in the final days of the 2020 campaign, while at the same time confirming the world's biggest economy is struggling to regain momentum as COVID-19 rates spike and the deadweight loss of the President's tariff wars linger.

America, which is still wedded to the distorting methodology of "annualising" quarterly gross domestic product numbers, is likely to be flooded by headlines showing the economy expanded by an eye-popping 32 per cent in the September quarter, after shrinking 31.4 per cent in the previous three months.