Let's take someone at random, Say Joe Klein at Time. Joe picks a topic for a column based on cocktail party chatter. He'll call up a friend, frequently the one he talked to at that party, and ask him for some quotes. He'll then ask that same guy for some other sources he can "confirm" things with. He will never, ever seek out an independent source. He won't do any independent research beyond reading the New York Times, Washington Post, and his own mag.
The important thing with Joe is to not upset any of his "sources." If they lie to him he'll believe the lie, frequently because he doesn't know enough to recognize a lie. If they tell him to bury something he'll dig a hole so deep it will never be found. Joe's first motive is to keep getting invited to those upscale cocktail parties. His job is not to tell the truth but to stay connected to people with power.
Matt Taibbi is a wonder. He actually read the collected works of Alan Greenspan and Ayn Rand in researching his book and studies the complex mechanics that brought the fall of AIG. He digs up people who know the inside scoop and Matt will actually listen to people who aren't A-list Beltway celebrities. There aren't 20 reporters in Washington who work as hard as Matt. Twenty combined.
Rage is the only quality which has kept me, or anybody I have ever studied, writing columns for newspapers. ~ Jimmy Breslin