Over in the US, the biggest day of this year's primary campaign is under way as 16 states cast their votes.

Strong performances from Donald Trump and Joe Biden indicate that the two front-runners for president have been determined.

American pollster Henry Olsen says Nikki Haley has no hope left of becoming the Republican nominee.

"This was actually a collection of states that she could have done well in if she had strength, but the fact that she lost most of them- that shows this is a campaign that should be over." 

LISTEN ABOVE

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• Trump declares 'BIG WIN' as Supreme Court clears him to run for president
• Trump's march towards Republican nomination continues, beating Haley in her home state
• Super Tuesday: Biden, Trump leading presidential race
• Supreme Court rules Trump can stay on Republican ballot- what comes next?