Bob Woodward, on Slate's so-far ho-hum "Diary on W" between himself, Oliver Stone, Ron Suskind, and Jacob Weisberg (who cares!), had this to say on Jeffrey Wright's excellent portrayal of Powell:
Jacob, you make note of the scene in W. where Bush and his advisers debate whether to go to war. In it, the Colin Powell character makes his case against the invasion. The problem is, as best I can tell, no such meeting ever took place. The president never called the National Security Council and the top advisers together to have a real knock-down, drag-out, come-to-Jesus meeting. It gives Powell more credit than he deserves. This is the broad meeting that Bush should have had to hash it out among his advisers. Powell's plea to the president in August 2002, which he recently affirmed, was that the administration needed to look at the consequences of war, but he never argued openly to the president that he should not invade Iraq.
(spoil-sporty, cynical, "Is nothing sacred?!?" emphasis added)