It has become one of the most vicious, important and divisive battlegrounds in the 2012 US presidential election.
Since it was legalised in 1973, the issue of abortion has polarised the US, but now the battle has been taken to a new level.
"What is abortion? Fundamentally it's the killing of an innocent child. If you can't get the life of an unborn baby right, I can't trust you with my taxes, education or anything else."
- Troy Newman, the president of Operation Rescue
Last year, an unprecedented number of laws have been passed across the US, all aimed at restricting abortion or reproductive rights.
But the fight goes far beyond the medical procedure, with Republican politicians even attacking the Obama administration for making contraception more readily available.
The US has seen more anti-abortion violence than any other country in the world. Since 1993, at least eight abortion providers, including four doctors have been killed. And there have been over 200 arsons and bombings against reproductive healthcare clinics since 1977.
Why is a medical procedure being reframed as a deeply divisive moral issue in the US?
Fault Lines travels to California to meet the next generation of frontline troops fighting to ban abortion, and to Ohio and Tennessee to investigate what lies behind the so-called war on women.
"It [Ohio's heartbeat bill] really only sees a woman as a carrier and she has no other right beyond her ability to reproduce. One of the reasons that these abortion bills are so dangerous is because it chips away at the notion of personal liberty, your right. And what can be more fundamental to your personal liberty than being able to control your own body ....
Women died trying to get back-alley abortions. Do we want to get back to that in the land of opportunities, the land of freedom? When did it become a sin and a shame to be a woman in this country? But that is what is happening in the 21st century in many states across this country and also in our congress and it's just absolutely shameful to me."
Nina Turner, Ohio state senator
Troy Newman, the president o