BEIJING — The tariff war between Washington and Beijing poses one of the biggest challenges yet for Chinese President Xi Jinping, potentially exposing his political vulnerabilities at a time when the Chinese economy is already slowing.

Xi needs to balance standing firm against U.S. pressure with the increasing urgency to reach a deal that would relieve battered exporters who have long underpinned growth and job creation, particularly outside the major cities.

The U.S. effort to win concessions from China on strategic industrial policies has put Xi's own prestige on the line. It also has cast into question the ruling Communist Party's social contract with the Chinese people: keeping authoritarian, one-party rule and ruling class privileges in exchange for delivering robust economic growth, better living standards and a higher global profile for China.