Why is Hillary Clinton struggling?

The US presidential election is now just six days away. The establishment politician Hilary Clinton was well ahead in the polls of Donald Trump. But since the FBI announced last week that they had discovered thousands of emails that might be relevant to the way Mrs Clinton had used her private email server, her poll ratings seem to have fallen off a cliff.

Nancy Soderberg was Deputy National Security Advisor to Bill Clinton when he was President. She told the Today programme Hillary Clinton is struggling because "she's having trouble getting past the mud to reach the voters."