In most mainstream media discussions about Colin Powell it is typically asserted both
(a) that he is the author of the "Pottery Barn Rule" meant to warn against putting troops amidst dangerous Vietnam-like circumstances and
(b) that he is a "good soldier" for the Administration and for that reason had held his views largely to himself until now.
Then his Presidential ambitions are discussed and his wife is often cited as a major reason he's not running.
I'd submit that there is another implication that no one usually mentions: that Colin Powell is an opportunist first and foremost.
Before you think me just a carping critic, ask yourself to whom Colin Powell proffers his primary loyalty: to the troops or the Administration? Can't choose? That's because his primary loyalty is to both--and that means, to Colin Powell. If Colin Powell was as resolute in his loyalty to American troops as much of Conventional Wisdom says he is, he would have spoken out or resigned as soon as he found out he had been deceived by the Administration (UN Speech) about the causus belli and the lack of pre-war planning.
For all his appearances of a statesman and a principled general, Colin Powell has been silent through revelation after revelation, and has done little to keep his supposedly cherished armed forces from sinking deeper and deeper into a Mideast quagmire. For what possible reason is he keeping his "powder dry" if not for his own benefit?
This latter fact both contradicts the mainstream media assertion that his either a virtuous leader or a viable candidate for the Presidency.