Striving for common ground, Obama urged the rival causes to co-operate on issues such as reducing unwanted pregnancies and easing the process of adoption. While engaging in vigorous debate in a "vibrant and varied democracy", he said, they should remain civil while fighting for their causes with "open hearts, open minds, fair-minded words".
Among those held was Norma McCorvey, known as Jane Roe in a landmark 1973 US supreme court case, Roe v Wade, which upheld abortion rights. McCorvey, who has since disavowed abortion, told Fox News: "I'm a peaceful protester, but if they come, they'll just take me away."