Ted Kennedy went from pro life to pro choice because he saw which way the political winds were blowing in the Democratic party.
George H.W. Bush went towards the pro life position because he thought it was advantageous politically in the Republican party.
Mitt Romney advocated a pro choice position while running in liberal Massachusetts and a pro life position which running in the Republican primary.
I don’t believe any of those men had strong feelings either way, they simply adopted the position the would confer the most political advantage to them.
Romney has told the story of his conversion in the debates and in interviews. He followed through by vetoing anti-life bills.
The Legislature over-rode his veto of the requirement to dispense the morning after pill to rape victims at hospitals.
He vetoed a bill in 2005 that would have allowed embryonic stem cell research in Massachusetts http://www.lifenews.com/2005/05/27/bio-997/ The Legislature over-rode that veto, too.
http://archive.newsmax.com/archives/articles/2005/5/31/154950.shtml
Romney has been very adamant that his pro-abortion views come from the heart, and that he committed to abortion as a young man in 1963 along with the rest of his family, after the (according to him) needless death of a loved one because abortion wasn't legal. Romney has never been more convincing or sincere than when he has explained the depth of his commitment to abortion. Romney abandoned the GOP because of Reagan, and at the height of the abortion wars supported moderate candidates until he eventually drifted into supporting solely democrats.
Romney was very deeply and passionately, and convincingly pro-abortion, more so than almost any republican we can name , he was not merely indifferent to it.