Colin Powell was one of the leading army officers of the late 1980's and early 1990's. He is a man of immense prestige and could well have had a chance of being the first Black American president. He was blocked by his wife, who feared for his safety and wanted to keep their family secrets from being exposed.
As soon as he could function in a more public way, General Powell showed himself to be politically center-left. That is despite his famous "Powell Doctrine", where the American armed forces would use overwhelming force to reduce American casualties. The "Powell Doctrine" is not inconsistent with being a moderate Liberal in politics, because it reflects his concern about the welfare of people.
I found Colin Powell's performance as Secretary of State to be disappointing, particularly because of the his apparent support of a pro-Palestinian slant in Israeli-Palestinian relations. While I sometimes blanch at some Israeli moves, I am pro-Israeli as a matter of policy. I also take a dim view of anti-Semitism, even though I am not Jewish.
So, Colin Powell's endorsement of Barack Obama was not unexpected. I was a bit bothered that Colin Powell's apparent motivation was that he was excited about the prospect of a Black president. I was bothered, because Colin Powell is orders of magnitude more qualified for the presidency than Barack Obama. Barack Obama, outside of his academic career, has accomplished little other than to have associated with the Weather Underground figures since the early 1980's and then participated in a few failed leftist causes and organizing activities. I would rather vote for Powell than Obama. There is nothing about Obama that motivates me to vote for him. He is all image and no substance. General Powell is a man of substance, in sharp contrast to Obama, so his endorsement of Obama is disappointing.