… is from page xxi of my late colleague Charles Rowley’s Prologue to the 1980 Cato Institute edition of Steven N.S. Cheung’s 1978 monograph, The Myth of Social Cost  (footnote deleted):
[N]o one should expect that governments will behave simply as social agencies whose sole or primary purpose is to maximize welfare. Research during the past decade … has confirmed lay suspicions that politicians maximize their own objectives, including power, income, ideology, and patronage subject to the “constraints” imposed by elections. For the most part, politicians are interested in externalities for their own sake as much as alcoholics are interested in the profitability of breweries.
DBx: Just as profits are fuel for businesses’s continued operations, opportunities to point to externalities (real or imaginary) that allegedly need to be ‘corrected’ with taxes or regulations are fuel for politicians’ continued operations.