Well, the US intelligence community knows just about what every country in the world has, what it's got in R&D (research and development) and how countries it could potentionally come into conflict with trains and fights. What you forget sir is that the US also has the best intelligence force in the world serveral times over. This is something that is too often overlooked when considering a conflict between nations on this forum.

You bring up China, but China does not come close to the US. Nukes would not be used in a conflict with China, first of all. Second, China can't hit the US with a conventional weapon from its mainland. The US can. China doesn't have much of a navy. The US has the most powerful navy in the world, and has ships and subs in the pacific that can strike China from where they are now. We won't even get into air superiority because it's a laughable comparison. The PLA is nowhere near as trained or equipped as the US Army and Marine Corps. In a conflict with China, ground troops wouldn't be needed until after China surrenders, and would be used as an occupying force to ensure compliance and stability in the country.

In a nutshell, the US could defeat China, bringing the war to China itself, within a month or two, give or take. It will be decades before China can even remotely begin to bring to the table what the US can.