Mr. Lighthizer — who is known as a tough negotiator with an encyclopedic knowledge of trade law — is a longtime China skeptic who has repeatedly cautioned Mr. Trump not to accept vague Chinese promises that fail to materialize. Mr. Lighthizer will be taking the reins from Steven Mnuchin, the Treasury secretary, who led previous rounds of negotiations with the Chinese but was unable to close a deal that satisfied the president.
“I do think that Ambassador Lighthizer is the best trade negotiator in the business,” Mr. Kudlow, the director of the White House’s National Economic Council, said during a briefing on Monday afternoon. “Mr. Lighthizer will be as vigilant as anybody in the business in monitoring this.”
The lack of specific commitments from China and the conflicting statements from United States and Chinese officials struck many analysts as a sign that the president may ultimately get far less than he is portraying to the public. Deep differences remain, particularly related to China’s treatment of American companies and what the White House says is a pattern of coercing technology and trade secrets from firms.
For instance, after leaving Buenos Aires on Saturday night, Mr. Trump told reporters aboard Air Force One that Mr. Xi had agreed to approve a tech deal it had previously rejected between Qualcomm, a San Diego-based chip maker, and a Dutch firm, NXP.
“You may also want to say that the President has agreed that if the Qualcomm deal that they rejected — which was one of the larger deals of its kind, which China rejected — if that deal came back to him, he would most likely approve it quickly, which is a big thing,” he said.
Qualcomm, however, had already abandoned its plan to buy NXP and is not expected to refile for approval: “While we were grateful to learn of President Trump and President Xi’s comments about Qualcomm’s previously proposed acquisition of NXP, the deadline for that transaction has expired which terminated the contemplated deal. Qualcomm considers the matter closed and is fully focused on continuing to execute on its 5G road map.”
Eswar Prasad, a trade policy professor at Cornell University, said that the warm feelings forged between Mr. Trump and Mr. Xi could soon cool if it appears that commitments are not being met.