Mark Halperin defends the sourcing practices he and John Heilemann used for their book Game Change:

To be sure, Time's Mark Halperin and New York Magazine's John Heilemann had the advantage of reconstructing the events after the fact, aided by operatives who were given a cloak of anonymity to dish and perhaps settle scores.

“One of the things people have said is that we've let the losers write the history, we've relied on people with axes to grind,” Halperin says. “We were so careful, so cautious in our sourcing. You won't see a negative portrait, a negative description that relies simply on a person with an ax to grind.”

That's what counts as being “so cautious in our sourcing” these days? Not relying on a single unnamed source with a vendetta? Quick, somebody give these guys an award!