He was never a democrat. During the Reagan administration, working first in the defense dept then National Security Advisor, he was politically unaffiliated. The vast majority of careerists are politically unaffiliated. He was recruited by both dems and pubs and became a pub.
And the issue is not his political affiliation, it is foreign policy affiliation. He is a foreign policy Realist.
People lose sight of the fact that the Realists were the dominant foreign policy group in the GOP for a long time and the NeoCon's dominance came about because George Bush was a very weak president dominated by NeoCon Dick Cheney.
If was only after the NeoCons came to power that the NeoCons were able to marginalize the Realists.
All of these Realists were highly respected in the GOP in earlier times but are now highly disrespected.
Kissinger? He's a self-loathing Jew. Brent Scowcroft and James Baker? They're jewhaters. Powell? He's a black racist.
Under the Realists, the military's job was to kill people and blow shit up. Under the NeoCons, the military's job is humanitarianism and nation building.
Your argument for powell as a realist dies here. He's the weak spined asswipe who begged GHWB not to march on Baghdad. He was the weakest link in the chain. Otherwise your Realist vs Neocon argument is spot on.
Powell was neither a Realist or Neocon. He was an unqualified affirmative action guy who looked good on camera.