A decade ago, after the 2008 global financial crisis, China seemed to save its economy by decoupling it from the rest of the world’s with a massive domestic investment program. Today, it is progress on the trade war with the United States, or the recoupling of China’s economy with those of other countries, that is seen as the way for it to regain momentum.

But to think in these terms is to miss the main point: The trade war has merely compounded an economic slowdown in China that is substantially of the country’s own making.

The deceleration is serious. In 2018, China’s gross domestic product grew by about 6.5 percent, the lowest rate since 1990. And part of the slowdown is a predictable result of deliberate government decisions, in particular policies that favor the state sector at the expense of the private sector — even though the state sector is woefully inefficient, whereas the private sector has long been the country’s growth engine.

The most striking evidence, documented by the Peterson Institute of International Economics in October, is the drop in credit to the private sector and the rise in credit to the state sector in recent years. The largest banks in China are state-owned and hew closely to government command. In 2013, 35 percent of bank credit to nonfinancial enterprises went to the state companies and 57 percent to private companies; in 2014, 60 percent went to the state sector, and only 34 percent to the private sector. (The rest went to enterprises with foreign or mixed ownership.) By 2016, the distribution was even more skewed: with 83 percent of credit going to state-owned or state–controlled companies, and just 11 percent to private firms. (According to the Peterson report, 2016 is the last year for which official data are available.)