The Washington Post is the premier newspaper in Washington, DC, and as such is one of the most influential papers in the world. Its editorial line is decidedly liberal, though on certain national security issues it can be unpredictable to the outsider.
The Post editors appear to enjoy hearing from critics. They publish outside comment in several areas of the printed newspaper and the website. They seem to like sparring with readers, and they often print harsh reader criticism.
Additionally the post has an Ombudsman, a rather independent in-house person who investigates allegations of wrongdoing and unwarranted bias, and who serves as a representative of the readers. It's a good idea to protest failures in the Post's Blackwater coverage by sending Letters to the Editor as well as letters to the Ombudsman. Here are the contact points:
General Letters the Editor policy.
Write to the Washington Post writers and editors by mail: Writer's Name, The Washington Post, 1150 15th Street, NW, Washington, D.C. 20071.
Write a letter to the editor by email: letters@washpost.com (Do not send attachments)
Contact Ombudsman Deborah Howell: ombudsman@washpost.com or call 202-334-7582.