I believe people can change. President Bush does as well; he knows this from personal experience, and so do I, hence my support of him and Miers. It's not like he was asking someone like Hillary...
I also believe people can change...in fact, I think most people do change; having said that, however, Miers is 60 years old...you'd think by this time in her life, it would be quite easy to see/know (from a paper trail) in what way she's changed or what her positions are (a red flag in itself)....the information we have gleaned from some of the paper trails she's left (i.e., supporting affirmative action) raises red flags.