In my 2021 Constitution Day post “And Secure the Blessings of Liberty,” a paean to the Preamble of the US Constitution, I asserted that the Framers used the phrase “the general welfare” in the Preamble (and in Article 1, Section 8, clause 1) to mean something akin to Kaldor-Hicks efficiency. In other words, they meant that the key goal of the Constitution was to implement policies that would benefit Americans on average without reducing the blessings of liberty.
Some readers questioned the Kaldor-Hicks claim. What follows constitutes my answer.
Ideally, the Framers would have made clear that by general welfare they meant Pareto-improving policies. In other words, they would have clearly stated that they wanted policies that improve the situation of one or more people without making anyone else worse off. Mutually beneficial trades are common Pareto-improving transactions that occur naturally whenever free economic entities interact. Pareto-improving public policies, by contrast, have to be well-thought out and potentially compensate those negatively affected by changed conditions.