it still has the largest military by orders of magnitude with bases round the globe.
That, too, is now being challenged by China.
In terms of manpower, the Chinese armed forces are the largest in the world, with over 2,000,000 active service personnel, plus a reserve force of some 500,000. (In terms of numbers, the USA comes in at third place - behind both India and China).
China has the largest navy in the world, with a current strength of 370 ocean-going ships - plus a coastal defence fleet of almost as many vessels. Furthermore, its ship building capacity is estimated as being some 270 times as great as that of the US. Not surprisingly then, its navy is still rapidly growing in size, with most of its ships having been built since 2010 (versus just 10% of the US Navy's ships). This navy has also demonstrated its growing global capability. Over the last several months, we in Australia have been reminded enough about that; with Chinese warships carrying out exercises (including live firing drills) just outside of Australia's Exclusive Economic Zone. Like the pre-WWI Imperial German Navy, that of China consists of a fleet of very modern warships. About the only edge the US Navy still has is its extensive, worldwide network of bases.
While the USA and Russia still have far more nuclear weapons than anybody else (each with over 5,000 devices at their disposal), the 600 odd nuclear weapons which China has are still enough to pose a serious threat. And just like its navy, China is rapidly building up its nuclear arsenal. The "missile gap" is closing at a rapid rate of knots!
America would now need to be cautious when assuming military superiority over China.
You know the old story about the word "assume"?
To ASSUME has a habit of making an ASS out of U and ME
