In a statement, Duffy said the Federal Railroad Administration terminated approximately $4 billion in unspent funding for “California’s High Speed Rail Boondoggle,” saying the $135 billion projected cost of the project could buy every San Francisco and Los Angeles resident nearly 200 round trip flights between the cities.

With the change, the Trump administration has also backed away from a signature effort to stay ahead of China in the A.I. race. The U.S. government had been concerned that the Chinese military could use A.I. chips to coordinate attacks and develop weapons and had also wanted to preserve the U.S. lead in developing A.I. systems.