Of course Obama is a centrist. It's how he gets the votes, the nomination, and how he polls as he does.
No. He won the nomination by NOT being a centrist, same as all his previous nominations. Now he has problems because his hard left past is being seen.
There are only a couple reasons to vote for Obama
1. You are a hard left liberal who agrees with his policies.
2. You are a racist. You are a racist in the same sense as those who push affirmative action are racists, they believe race should be used as justification for reward or punishment.
3. You are an deluded. You believe the "Change" rhetoric and fail to recognize what type of change Obama really wishes to bring.
4. You absolutely want out of Iraq immediately and no one or even group of issues can possibly out weigh that factor.
I think the majority of people in the middle who are supporting Obama fall into a combination of groups 3 and 4.
Racism will not loose the election for Obama but it may win it.
Powell may carry respect but he will have far less if he supports Obama.
Reason 1 should not apply given what I have seen of Powell.
Reason 3 should not apply because I think he is smart enough to see Obama for what he is.
Reason 4 is most likely not the factor. I believe Powell wants out but doubt he would sacrifice the nation to get it, especially with improvements starting to appear.
That leaves Reason 2, which is not uncommon these days.