A historic Supreme Court ruling has expanded the scope of US presidential power.

The United States' top court has ruled six to three that former presidents can be granted immunity from prosecution over acts done in office.

This means Donald Trump's alleged role in the Capitol riots in January 2021 likely won't make it to trial before the election.

But Cornell University law professor Randy Zelin says the decision isn't as earth-shattering as it's being made out to be.

"The Supreme Court is saying - we're going to take it case by case, there may be a presumption that the President was acting in an official capacity, but that presumption can be overcome." 

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