Damon Linker traces the history of the term:
[Professor of psychology Jonathan] Haidt claims to have found that American liberals and conservatives merely differ on which aspects of common sense they prize most highlywith liberals tending to esteem fairness and care and conservatives leaning toward loyalty, respect, and purity. If this finding ends up being confirmed by further studies, it would show not that one ideological outlook or another is more commonsensical than other, but rather that the content of common sense is somewhat fluid or changeable within certain broad parametersand that to a considerable extent it mirrors our political opinions and ideological commitments (or vice versa).
Yglesias spins.