The Chinese balloon shot down off the South Carolina coast was part of a large surveillance program that China has been conducting for “several years,” the Pentagon said Wednesday…When similar balloons passed over U.S. territory on four occasions during the Trump and Biden administrations, the U.S. did not immediately identify them as Chinese surveillance balloons, said Brig. Gen. Pat Ryder, the Pentagon press secretary. But he said “subsequent intelligence analysis” allowed the U.S. to confirm they were part of a Chinese spying effort and learn “a lot more” about the program.