I'm not a big believer in the slippery slope argument. "We can't let Catholics have the vote or the Pope will rule England! We can't let gays get married or the family and thus freedom will collapse! We can't let women have the vote or the nanny state will consume our freedoms..." Well, maybe that last one. Kidding, kidding.
The thing is, whether there's a slippery slope or not, you have to do what's right — give people their freedom and equality before the law — and then deal with the consequences as they come. It's the only way because we never really know what the effects of our actions will be. So - trust to freedom and deal.
But with abortion, it's different. Death has a certain, oh, finality about it that makes its consequences more or less foreseeable. To wit, when yer dead yer dead. So, followed to their only rational conclusion, unfettered abortion "rights" are absolutely guaranteed to strip the rights to life, liberty and the pursuit of happiness from the generation up ahead.
Abortion is a one-sided suicide pact — a bad deal that gives women of the future the ability to end their pregnancies at will in exchange for never being born themselves! Chelsea Clinton doesn't really wish her great grandparents had had the right to prevent her life from occurring. Why then should she wish non-existence on the Chelseas we don't yet know?