In a remote Chinese desert, a vast military complex is taking shape that some security scholars say appears built to ensure no American first strike on China's nuclear arsenal could reliably knock out Beijing's ability to hit back. China's nuclear missiles can already reach any American city. Now, satellite images show Beijing is building a sprawling web of launch pads, bunkers and communications nodes near the isolated nuclear silos that hold the Chinese military's longest-range missiles.The ability to protect its desert silos is key to China's stated goal of forging a minimal but credible nuclear deterrent – a policy grounded…