Unlike the Soviet Union, the People's Republic of China isn't anything resembling a peer of the United States when it comes to nuclear weapons. Yes, the PRC has nukes. And, yes, the PRC even has nukes capable of hitting the United States. But it doesn't have all that many, nor as they particularly sophisticated. What's more, as Kier Lieber and Daryl Press note in the current Atlantic, the gap appears to be growing, "the United States is pursuing capabilities that are rendering MAD obsolete, and the resulting nuclear imbalance of power could dramatically exacerbate America’s rivalry with China."
America's "counterforce" capabilities -- the ability to "win" a nuclear war -- are much, much, much more advanced than China's. This means China can't be confident that it's second-strike nuclear deterrent would prevent us from nuking China. But that means China may, in a tense standoffy moment, feel the need to be much more proactive with its own arsenal than you would expect in a MAD situation. If the Chinese believe an America first strike would result in victory, then launching a first strike looks like a good idea for the Chinese. And if Americans think a Chinese first strike makes sense from a Chinese perspective, but that an American first strike will result in victory, then a US first strike looks like a good idea for Americans. But if the Chinese knows that . . . and if the Americans know the Chinese know that . . . and the Chinese know the Americans know they know that . . . etc., etc., etc.
At any rate, it's a fascinating -- and disturbing -- article. For more on this see Benjamin Schwarz's column written where their academic study was completed, this post from Brad Plumer and this one one Robert Farley both from back in 2006, and Lieber and Press' March '06 article in Foreign Affairs.
National Archives photo of Operation Ivy via PINGNews.