Liberals want to use racketeering laws to prosecute so-called climate-change skeptics. But the real conspiracy may be between plaintiff lawyers and Democratic politicians who have ganged up to shake down oil companies.

San Francisco, Oakland, New York and Seattle have sued five global oil giants—BP, Chevron, ConocoPhillips, ExxonMobil and Royal Dutch Shell—for billions in future damages from climate change. Brass-knuckled plaintiff firm Hagens Berman Sobol Shapiro has been shopping around the lawsuit to other cities desperate...