The real question is not why the stock market is down this week. It is why it is down so little.

After all, the world’s two largest economies have seemed to be hurtling toward a major escalation of their trade war. American officials have complained that Chinese negotiators have been playing a bait-and-switch, backing away from concessions they had agreed to.

President Trump said the United States would raise its tariffs on $200 billion of Chinese imports to 25 percent from 10 percent on Friday, and begin taxing the remaining $325 billion of goods at that rate “shortly.” For a while, it was unclear whether negotiations would resume at all this week.

[President Trump taunted China by tweet on Wednesday.]

If trade talks did disintegrate, even with the arrival of high-level Chinese officials in Washington, the economy would be in danger of experiencing a meaningful downturn and potentially a recession. Economists at Moody’s Analytics, for example, expect it would subtract 1.8 percentage points from G.D.P. growth and cause unemployment to rise.

It would particularly hammer the financial results of some of the prominent American companies that either import Chinese goods or rely on the country as a major export market.