Negotiators from the two countries will try to bridge their divisions as talks begin in earnest in Shanghai on Wednesday. But the deep divisions between the countries suggest another protracted round of talks may be needed before any agreement can be reached.

The text that the two countries have been negotiating is highly secret. But American and Chinese negotiators appear to still have significant differences of opinion over how China should enshrine changes, including new protections for American intellectual property in its laws and regulations, how many American products China would agree to buy as a result of the deal, and how many of Mr. Trump’s tariffs on $250 billion in Chinese goods would remain in place after an agreement is struck.

The president continues to insist that he faces no immediate deadline to reach an agreement. On Tuesday, he repeated his claim that the United States economy is benefiting from the billions of dollars his tariffs are generating and that all the pain of the trade war was being felt on the Chinese side. That view is not supported by businesses and economists, who say Mr. Trump’s trade war is starting to take a toll on the United States economy.

Chinese leaders have also insisted that the country can withstand the pressure of the trade war as it waits for a better deal from the Trump administration, or another president.

In reality, both economies are presenting more of a mixed picture, with the effects of the trade war clearly being felt, but not so intensely that their leaders can’t ignore it.

The Chinese economy is decelerating gradually, but further increases in the country’s already giant infrastructure spending have cushioned the shock. Chinese exports to the United States have fallen 8.5 percent in the first half of this year compared with the same period last year, while exports to the rest of the world have been up slightly.

Sales of cars and other big-ticket purchases in China had tumbled sharply last autumn when Mr. Trump broadened his tariffs to $250 billion a year of goods from $50 billion. But Chinese consumer confidence now seems to have flattened at a level best described as still very glum, but not rapidly deteriorating further.