Pollster explains why Harris leads in Iowa poll

A new poll of voters in Iowa suggests that Kamala Harris is leading with 47% over Donald Trump's 44%.

The survey was released by the highly regarded pollster Ann Selzer, and it questioned 808 likely voters in the state.

Harris's lead, driven by women and independent voters, is still within the margin of error, 3.4 percentage points.

"You'll note that neither of the major candidates gets to 50%, so there's still a little squishiness in what could actually happen come Tuesday," Selzer told BBC News.

Trump won Iowa by nearly 10 points in each of the last two elections.