Far more than simply a market crisis, the turmoil on the Shanghai Stock Exchange is viewed by China’s leadership as a potential security threat to the regime.

That helps explain the barrage of measures unleashed by financial authorities to counter a sudden market downturn that threatened to shake public confidence in the government.

In that sense, the unprecedented rescue moves, including a multibillion-dollar fund set up by Chinese brokerages at the government’s behest to buy blue chips, is a preview of what’s to come following the passage last week of a national-security law that massively expands the definition of threats to the state to cover almost every aspect of domestic life, including “financial risk,” as well as international affairs. The law explicitly states that economic security is the foundation of national security.

This week’s attempt to bail out the market underscores the deep misgivings of foreign investors, who fear the legislation gives the government a new mandate to override open-market principles in the name of combating real or imagined dangers to the Communist Party.