Both candidates are expected to sew up their nominations by the start of next month.
ADVERTISEMENTUS President Joe Biden and his predecessor Donald Trump both won big in the US's Super Tuesday primaries – and Trump's only noticeable challenger had little to celebrate.
Nikki Haley, the former governor of South Carolina, won only one state, the small Democratic stronghold of Vermont.
Though her campaign said staff were jubilant, she gave no victory speech.
Donald Trump, by contrast, quickly declared victory. He's moved on from these primaries, and so has Biden.
Both men are now firmly pivoting to what looks set to be a repeat of their duel in 2020 –and the US is bracing for a brutal eight months of campaigning.
Watch the commentary by Philip Crowther in the player above.