BEIJING — One year ago, when he began a multibillion-dollar trade war with China that shook the global economy, President Trump demanded that Beijing end lavish government spending aimed at making the country a world power in computer chips, robotics, commercial aircraft and other industries of the future.

Today, as the two sides struggle to reach a truce, the Trump administration is finding just how difficult that will be.

Trade talks between the United States and China nearly ground to a halt this past week, and a seemingly intractable dispute over subsidies is a big part of it. Robert E. Lighthizer, the United States trade representative, accused China last Monday of reneging on what he described as “good, firm commitments on eliminating market-distorting subsidies.” Vice Premier Liu He, the leader of China’s negotiating team, said that it was normal for negotiations to have ups and downs, but has also nodded to the subsidies issue in vowing repeatedly over the last several days not to bend on China’s principles.

President Trump on Friday raised tariffs on $200 billion a year worth of Chinese goods, hitting goods leaving China’s shores as of that day. He has directed Mr. Lighthizer to start on Monday the long process for raising tariffs on all Chinese goods.