Listening to the Alito confirmation today, many of the questions were about abortion. Abortion used to be left up to states. It was legal in some states and not in others. Women with little resources were unable to travel to states where abortion was legal. They had to get really cheap, really risky abortions, and some of them died.
In spite of the slander of pro-lifers, nobody is in favor of abortion. Abortion is horrible. Ask anybody who had one. The trouble with trying to prohibit abortions in the law is that abortion is fundamentally an act between two consenting adults; or even just one if a woman self-aborts. Pro-lifers will claim that there are two people involved but women interested in an abortion deny that.
It's extremely expensive (and as an economist, when I say "expensive", I don't mean just money; I mean all costs incurred whether money or people's time, or any physical resource expended which hasn't been paid for by the money, or any moral cost incurred, or anything that didn't happen instead) for a third party to interfere with the actions of two willing participants. Look at pornography, prostitution, drug dealing, gun running, or anything done on the black market.
The constitutional justification for interfering with state laws concerning abortion is pretty thin. It is, to my mind, a justification for doing what people want to do anyway. People became tired of paying the cost of interfering with abortions, so abortions are now legal everywhere in the US. I understand people's frustration, but that battle should have been fought at the state's rights level.