During the height of the 1950s Red Scare, when there were Communists under every bed and spies in every closet, America saw threats to its national security everywhere. Justifiably, there were purges of those who really sought to sneak state secrets to the Soviets. War plans and bomb-making schematics were the most important of those confidential documents. Accusations abounded; not everyone was guilty. Fast forward to 2020, and the new Red Scare is Beijing, not Moscow. The fear is that China’s long reach is not only touching but grabbing some of America’s dominant industries, institutions, plans and, of course, people. Scientists and researchers are in the crosshairs. Dr. Charles M. Lieber, the Harvard professor who recently was arrested by U.S. officials for allegedly sending research to China — and lying about it to American authorities — pleaded not guilty on Tuesday.