Reagan was a Democrat and living in the Hollywood group-think bubble. It's feasible to believe he had never really thought about abortion as anything other than a vague concept.
...But Mitt Romney now expects voters to believe that he finally "thought the issue through" at 57 years old (right before pondering a Presidential run)? Maybe his indecisiveness stems from the fact that (as far as I can tell) the LDS have no official stance on abortion.
If he honestly had a change of opinion, well, I guess that's great...but what rings untrue to me is his explanation of the stem-cell debates changing his mind that the embryo is a life... Not all the video and pictures of actual abortions, but a microscopic thing in a Petri dish? The descriptions of partial-birth abortion never roused his inner conscious, but a embryo did it? Excuse me if I'm skeptical.
"It was during that discussion, which related to something called embryo farming, which is taking donor sperm and donor eggs, creating embryos, experimenting on them and then destroying them in 14 days, that it came home very forcefully to me that the Roe v. Wade mentality had cheapened the respect for human life in this country.
"And for that reason, I made it very clear that I am pro-life.” In 2005, he declared: "I am pro-life. I believe that abortion is the wrong choice except in cases of incest, rape, and to save the life of the mother.”
Al Gore’s stance on abortion shifted to the left as he eyed the White House. In 1987, he stated: "During my 11 years in Congress, I have consistently opposed federal funding of abortions,” which he called "arguably the taking of a human life.”
By 2000, when Gore was running for president, he declared: "My position has changed. I strongly support a woman’s right to choose.” (source)
Oh, I know, I know...change means growth and the ability to be flexible --or it means that someone actively campaigned on important issues they hadn't even vetted in their own mind. And it may just mean they lack the conviction to stand by their beliefs...