I'll tell you what happened...
We started playing the game with Democrats because something had to be done about the onslaught of left wing politics being presented in the form of legislation. The Republican Party started taking positions on issues, and lost sight of the core of the Reagan revolution...
Either the Constitution is amended to weigh in on the matter for the federal government or, the answer is… a state issue whether for or against whatever the issue is.
The United States Constitution was originally written to reflect a federal government that was extremely limited in legislative authority. The things that were given to the federal government as things that they could control was spelled out in clear and very unambiguous language and in Article 1, Section of the Constitution it even spells out exactly what those limits of power are.
The Civil War happened and one of the results was that the federal government, that is the mandate for the exercise of federal authority over states, was set. The cause was good, but the results ended up being a Republic killer. In particular the 14th Amendment, which was written as a post Civil War reconstruction amendment, has been used to expand the authority of the federal government to such a degree that the notion of the state being the seat of power in the United "States" was swept aside because we couldn't use the Constitution to iron out our differences. The south lost the war, but were kicking against the goad in an attempt to keep from being forced to accept equality for all human beings regardless of race in particular.
The14th Amendment was introduced to allow the federal government to intervene in the affairs of a state who purposed to deprive citizens of this country of life, liberty and property. It reads...
No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
So here we are talking about the issue of abortion in a federal Presidential political campaign. Why is that?
The first thing we need to recognize is that we really should address abortion through the Constitution. It wont work, but we need to go through the process. Two amendments need to be introduced. One to declare abortion a right, and the other to declare when life begins and to protect it past that point. The latter would stand a very good chance of passage if it was reasonably presented (e.g. 3rd trimester with access to special courts if the mother's life was in danger).
The answer needs to be that we restore the Constitutional Republic and deal with the issue as the Founding Father's had intended us to deal with these types of issues. Where we failed in the process that led to the Civil War was that they lined up on either side of the issue and gathered the political power necessary to win the debate. The result was that it ended up in a stalemate and the southern states were content to allow slavery in particular remain exactly where it was... stalled. The war itself erupted because the federal government was pressuring the southern states, and they wanted to maintain their sovereignty as guaranteed by the United States Constitution and were willing to fight for it.
The south was actually correct on the issue, but of course morally wrong for refusing to apply the human rights guaranteed under the Constitution to all human beings regardless of their race. The result is that we have turned into a nation that is top heavy in federal, who has lost the vision of the Founding Fathers in a Constitutional Republic of limited government and power, and one who is now entering a stage where the issues that separate the right from the left are beginning to boil. We can not afford as a nation to be sucked into another set of circumstances like those that led to the Civil War, and as much as I oppose abortion and any political candidate who supports it, I believe the true answer lies within fixing the Republic.