Promote laissez-faire economic and social policies" would be a concept supported by social Darwinism, since this entails the government letting the free market regulate itself, in a manner of the "survival of the fittest".
Step-by-step explanation:
Social Darwinists believed that the life of humans in the community was a contest for existence ruled by “survival of the fittest,” a phrase introduced by the British philosopher and scientist Herbert Spencer.
Social Darwinism, a term coined in the late 19th century to describe the idea that humans, like animals and plants, fight in a contest for existence in which natural determination.