Williams writes: “Pragmatic is now most often used, especially of politicians and politics, in contrast either with dogmatic or with principled, according to point of view.” I find this definition interesting, since the latter would imply that it may be difficult to be both pragmatic and principled!
I would prefer the opposition, or contrast, between pragmatic and cartesian, the latter implying adherence to reason and logic. But Williams concludes: “…the word has been useful as a dignified alternative to unprincipled or timeserving, especially in political movements which profess a set of beliefs and which decide, under pressure, to neglect discard or betray them, but with a show of skill and intelligence.”
Related: article on Cartesianism on Wikipedia. Note that this article does not oppose the two!