A shock poll from the state of Iowa has added another swing state to the list of US election battlegrounds as Kamala Harris and Donald Trump fight for every last vote. The Des Moines Register poll, which landed on Saturday evening, puts Harris 3 points ahead in the state, which has not voted for a Democrat for president since backing Barack Obama in 2012. It carries a mere six votes in the Electoral College, but losing it would greatly complicate Trump’s path to the presidency as he seeks to peel as many states away from Harris and the Democrats as possible. While the poll is an outlier, it ca…