You can learn much even from people you disagree with.  Do not accept everything you read whole cloth, but good argument is the forge for clear thinking.  The following are a selection of popular columnists that often have something interesting to say about politics as well as the human condition.
David Broder Bill Buckley Georgie Geyer David Ignatious
Jonah Goldberg Richard Cohen Michael Kinsley Robert Kagan
Arianna Huffington Ellen Goodman Mary McGory Charles Krauthammer
Michael Kelly Jim Pinkerton William Raspberry Robert J. Samuelson
George Will Donnella Meadows Marjorie Williams E.J. Dionne Jr.
Garry Wills Tony Snow Jim Hoagland Richard Reeves
David Shribman Ted Rall Drudge Report