If they change because they actually believe in the new position, sure.
Why would I believe that just because she’s changed her public stance from an unpopular one to a popular one, she’s just not doing it to court votes and will, out of the public eye, continue her old stance? This is why people don’t trust politicians that flip flop. It makes them look like they have no values of their own, just opinion polls.
So? I honestly don’t care what’s in a politician’s heart-of-hearts; I’m more concerned about what they do. I’d rather have a politician who supported marriage equality because they saw that was the way the political winds were blowing than one who steadfastly opposed it because they had a deep, heartfelt commitment to bigotry.