Torrential rains and floods across the southern half of China have besieged cities and towns for days. Nearly 200 people had died by Friday in drownings, landslides and as buildings collapsed, including 35 buried by a landslide in the far west. Nearly two million people have been moved to safer ground while swollen rivers and lakes strain dikes and dams. For China’s leaders, the floods are a test of their ability to deliver on their promises of safety for citizens.