Democrats must link Mr. Trump’s trade agenda to his racism and xenophobia. They should emphasize that in Mr. Trump’s worldview, every import is an insult to him, and every trading partner is a villain trying to rip us off. Thus, tariffs and walls must be erected to protect us from a hostile outside world. These actions are invariably based on bogus rationales, such as Canada as a security threat or Argentina and Brazil pushing down the value of their currency (in fact, they’re trying to prop them up).

Once Mr. Trump’s trade war with China has been firmly rejected, candidates must explain their replacement to the pre-Trump, United States-China status quo. A key starting place is to recognize the futility of trying to get China to significantly change its internal economic model. We have no more business insisting it stop directly subsidizing its industries than it does insisting that we stop indirectly subsidizing ours through, for example, the highly favorable tax and patent treatment of our finance and pharmaceutical sectors.

A progressive China trade policy should not shy away from targeting specific “beggar thy neighbor” actions by China or any other trading partner, including dumping specific goods below cost to capture market share or artificially depressing the value of their currency (a recent, bipartisan bill could help realign manipulated currency values). But such defensive actions are insufficient.

Democrats need to go on offense, which in this case implies something with which progressives should be particularly comfortable: public investment in research and production to increase our international competitiveness. Conservatives may dismiss such action as “picking winners,” but the fact is we already pick winners all the time. We just do so through the tax code, based not on a strategy of competitiveness but on who has the best-connected lobbyists.

A much more focused trade policy would do something our trade competitors, including China itself, does: to see around the next corner of global demand where no country has yet to establish a comparative advantage. China did so with the assembly of consumer electronics, but that’s a low value-added play. We should do so in green technology.

For example, with support from the European Union, the Swedes were recently seen taking up this challenge in battery production. Their goal, according to the Swedish manufacturer Peter Carlsson, is “to create a European supply chain that links electric-car manufacturers with battery makers, all powered locally by solar and wind plants and using European workers and know-how.” Their competition: China and South Korea. We’re not even in the game.

Complementing this market-making initiative, Democrats need to help the people and the communities that have been hollowed out by the loss of factory jobs. Such efforts must go far beyond “trade adjustment assistance” (government assistance, like “job relocation allowances,” to workers displaced by trade), which workers themselves aptly dismissed as “burial insurance.” People don’t want handouts (attention, Andrew Yang), they want to be productive.