According to Lying In Ponds, the most partisan columnists so far this year are:
Paul Krugman, the #1 most partisan Democrat (score of 70, for 180 negative Republican references vs. only 12 negative Democratic references)
Ann Coulter, the #1 most partisan Republican (score of 75, for 176 negative Democratic references vs. only 13 negative Republican references)
In contrast, economist Thomas Sowell has a score of 15 (30 negative Democratic references and 27 negative Republican references), George Will has a score of 14, and David Brooks has a score of 2. The higher (lower) the score the more (less) partisan the columnist.
From Lying in Ponds: The views of pundits who are excessively partisan cannot be taken seriously (like advertising), because their ulterior motives or uncontrolled biases are certain to frequently contaminate their judgements.
Conclusion: Do not take Paul Krugman or Ann Coulter seriously.