A Latin saying favored by 19th-century revolutionaries reads: Fiat justitia, et pereat mundus. "Let justice be done, though the world perish."
That is not an economist's way of thinking, but it does seem to be how competing ideologues and moralists increasingly view decisionmaking.
Consider polices advocated by many on the left or the right and it soon becomes apparent that they are thinking not practically, but almost theologically — unable to tolerate compromise or trade-offs.
Economics is all about allocating scarce resources. There are no gains without costs. Is one really prepared to let the world perish rather than allow the smallest injustice?
Moralists don't perform cost-benefit analyses to reduce the most sin with the least effort. They don't think of trade-offs among the Ten Commandments. Such thinking for them carries a whiff of the devil's sulfur.
With politics becoming a secular religion, and its practitioners taking similarly inflexible stands, it might be worthwhile to consider how an economist would approach some of the vital issues today.
In understanding people's preferences, economists consider not what they say but what they do — their "revealed preferences." Many today believe, with justification, that climate change poses an existential threat to the planet. Yet if one reflexively opposes nuclear power or fracking for natural gas, all of which can reduce carbon emissions even if they are themselves not perfectly green, can one really believe in imminent global catastrophe? Or is one thinking like a moralist who will not choose one sin over another?
The Green New Deal, endorsed by many progressives, proposes to phase out internal-combustion engines and retrofit all buildings in the U.S. But it also calls for guaranteed jobs, suitable housing and healthy food for all. Surely, if the planet faces a climate emergency, one should postpone other causes. Insisting on addressing all problems at once means that none is particularly urgent.