On Friday's AM: US President Donald Trump again threatens to North Korea, saying his warning to unleash 'fire and fury' on the rogue regime perhaps wasn't tough enough; the Federal Parliament's decision to take the same-sex marriage debate to a postal plebiscite faces a challenge in the High Court today; and new research finds that children from disadvantaged backgrounds are more likely to develop heart-related illness in later life. This is an early edition of AM. The complete 30 minute edition will be available for download at 9am.