Are there ethical considerations that need to be factored in as part of assessing the merits of a "trade war" with the People's Republic of China?
There are three broad ethical frameworks that are in conflict which make answering this question difficult. The ethics of a trade war depend, in large part, upon which set of values you choose to prioritize.
The prevailing view, up to the 2016 elections, drew heavily on the "democratic peace", the "great capitalist peace" and the rising GDP/democratization theses as well as the precepts of the liberal school of thought in international affairs. Interdependence between the Chinese and American economies would create conditions to prevent conflict, channel China's "rise" into the so-called "responsible stakeholder" that would shoulder more of the burden in international affairs (implicitly lessening the burden on the United States), lift people out of poverty, and set conditions for gradual, evolutionary democratization that would cement better Sino-American relations and benefit the cause both of global order and of human rights. A trade war risks all of that by incentivizing conflict and removing the linkages which might cushion tensions, and, by negatively impacting the standard of living of both Chinese and Americans who depend on the trading relationship, can be seen as unethical in that regard.
A counterargument that draws on both democratic and realist critiques argues that the trading relationship has allowed a Chinese regime that is antithetical to liberal values at home and to the existing international system to acquire more power and resources, which it has used to both pursue greater capabilities to act in the world (often at odds with U.S. preferences) but also to more effectively repress its citizens at home. Disconnecting the U.S. and Chinese economies, despite the short-term pain, is ethical in the long run for removing any tacit U.S. support for China's unliberal practices at home which are at odds with American values but also to lessen the economic and technological bases from which China is emerging as a near-peer competitor to the U.S.
A third view is the transactional one: does trade with China help or hurt Americans? Here, the ethical assessment is mixed, for some Americans have benefited from the relationship, while others have not. Assessment therefore is in the eye of the beholder as to whether the "right" people are being helped or hurt either by the trading relationship or by the trade war.
What is interesting in observing the 2020 election race is to see elements of all three critiques being deployed; criticism of the Trump administration for plunging the U.S. into a destabilizing trade war with China, but also concerns being voiced about how the assumptions of U.S. China policy over the last thirty years need to be revisited because of their impacts on American workers or because of China's internal and foreign policies.
It is often said that Americans "don't vote" on foreign policy issues, but my guess is that "China" will serve as shorthand during the 2020 primary and general election campaigns for a variety of these issues.