I'm pretty certain that China has at least 800 nuclear warheads currently ... they just cite the 300 number to give the misleading impression of "minimum deterrence." 300 is just not enough ... especially considering that a lot of the warheads are on older missiles like DF-5 or DF-31, which are less effective. Even 800 may not be fully adequate for a second strike. I remember a couple years ago when the "Underground Great Wall" was exposed, Western scientists immediately negated the possibility of such tunnels housing nuclear weapons ... something tells me they just want China to serve as the posterchild of nuclear arms control at a time when North Korea and Pakistan are ramping up their stockpiles.@plawolf, it's not just about the stock of warheads and delivery systems, it's about how many of them survive a first strike. Your example with 300 warheads destroying the US implies that all 300 survive the first strike and make it through the missile defenses. Optimistically, 90% would be destroyed or inoperable. 50% of those surviving would make it through the missile defenses. I don't think 15 warheads would destroy America.
China's defense budget is between $350 and $500 billion (in PPP, the only worthwhile way to calculate it) and growing like a weed. China ramping up its nuclear arsenal from 300 to 2000-3000 over a period of 10-15 years is comfortably achievable. Now that China has the delivery systems like the DF-41/JL-3/DF-5C to get the job done, it's exactly the right time to do it.