Partisan

Because I almost always support the candidates of one party a friend recently described me as "partisan." I indignantly rejected the label, explaining vehemently that I supported candidates based on my political philosophy, not the party label. But Douthat does have a point:

.... Up to a point, American politics reflects abiding philosophical divisions. But people who follow politics closely — whether voters, activists or pundits — are often partisans first and ideologues second. Instead of assessing every policy on the merits, we tend to reverse-engineer the arguments required to justify whatever our own side happens to be doing. Our ideological convictions may be real enough, but our deepest conviction is often that the other guys can’t be trusted.

How potent is the psychology of partisanship? Potent enough to influence not only policy views, but our perception of broader realities as well. .... [which Douthat illustrates as he continues]

The Partisan Mind - NYTimes.com