What to expect from Trump's State of the Union address on Tuesday night

US president Donald Trump said his address would be lengthy. His 100-minute speech last March was the longest presidential address to Congress in modern history. Picture: Evan Vucci/AP

US president Donald Trump will deliver the traditional State of the Union address to Congress on Tuesday night (2am Irish time) at a fraught moment for his presidency, with his approval ratings slumping, anxieties rising over Iran, and Americans struggling with the cost of living as the November midterm election nears.

The televised prime-time speech to Congress, his second in the 13 months since returning to the White House, offers Trump a chance to persuade voters to keep Republicans in power. But it comes as he faces stiff political headwinds at home and abroad.