Herman Cain's Abortion Flip-Flop

Herman Cain was interviewed by CNN's Piers Morgan this last week and when being asked about the issue of abortion, Cain responded by saying “I believe that life begins at conception, and abortion under no circumstances." However a few months before he said "it ultimately gets down to a choice that that family or that mother has to make". Cain has recently emerged as a serious candidate and many Anti-Abortion Republicans are questioning his abortion views. However, back in 2007 when President Obama was running he at first argued against abortion when he was running in the primaries. But later once Obama got the nomination he argued for pro-choice. Does this mean candidates agree with there parties views of abortion after they are criticized?