The whole episode is a reminder that history is a complicated thing. The traits that lead to disaster in certain circumstances are the very ones that come in handy in others. The people who seem so smart at some moments seem incredibly foolish in others.
The point Brooks doesn't emphasize is that the pre-surge policy of too few troops was also a Bush-Cheney-Rumsfeld policy. Bush, let us remember, opposed the surge before he was for it. John McCain, on the other hand, has been advocating the surge since 2003.