Who are a political reporter’s best sources? 

The best sources are the politicians themselves. In Idaho, we’re fortunate, because I can almost always reach a state legislator, and, if it’s a significant story and I’m dogged about it, our congressional delegation and the governor. Of course, they are looking out for their own interests, but that’s just another filter to consider. Other good sources are well-informed bureaucrats, the staff of elected officials, lobbyists and interest groups. Finally, I never regret talking to ordinary people about the issues they care about. They often have questions that would never have occurred to me, and care about issues that we’re missing. And, as with all reporting, talking to sources face-to-face is better than the phone.

[From Reporting That Matters, p. 210]