As one of the most contentious issues in US politics, abortion is expected to be a pivotal factor in the presidential election. At the same time, tens of millions of voters across the country will decide whether to guarantee abortion rights in their states’ constitutions. Abortion will be on the ballot in 10 US states, including swing states that could change the course of the election and the battle for the control of Congress. One in six US women of reproductive age say that abortion is the most important issue in this year’s vote, according to a recent analysis by health policy organisation…