During the early -to-mid-1800s, what was the primary subject of american artists

Pop art started with the New York artists Andy Warhol, Roy Lichtenstein, James Rosenquist, and Claes Oldenburg, all of whom drew on popular imagery and were actually part of an international phenomenon. Following the popularity of the Abstract Expressionists, Pop's reintroduction of identifiable imagery (drawn from mass media and popular culture) was a major shift for the direction of modernism. The subject matter became far from traditional "high art" themes of morality, mythology, and classic history; rather, Pop artists celebrated commonplace objects and people of everyday life, in this way seeking to elevate popular culture to the level of fine art. Perhaps owing to the incorporation of commercial images, Pop art has become one of the most recognizable styles of modern art.

trade regulation is a field of law, often bracketed with antitrust (as in the phrase “antitrust and trade regulation law”), including government regulation of unfair methods of competition and unfair or deceptive business acts or practices. antitrust law is often considered a subset of trade regulation law. franchise and distribution law, consumer protection law, and advertising law are sometimes considered parts of trade regulation law.

in general the theory of economics says that the more open to trade a country is the better   the result for the same country and the whole economies.

in real life countries impose taxes, quotas, etc which is not so good for the economies.

this kind of commercial war between the usa and china is slowing down the growth of the whole world so we can say that it is a draw back of trade regulations. and the free trade agreements are benefits of trade regulations.