
The U.S. economy is the largest economy in the world.       But it wasn't always the largest.
 
 And it's unlikely to remain the largest economy for much longer.
 
 "As Alexander, Rome and Britain fell from their positions of  absolute global dominance, so too has the US begun to slip," Reid writes  in a new note to clients. "America’s global economic dominance has been  declining since 1998, well before the Global Financial Crisis. A large  part of this decline has actually had little to do with the actions of  the US but rather with the unraveling of a century’s long economic  anomaly. China has begun to return to the position in the global economy  it occupied for millennia before the industrial revolution."
 
 One look at the chart and it's pretty clear that it may not be very long before we start saying the U.S. is No. 2.
 
 "Based on current trends China’s economy will overtake America’s  in purchasing power terms within the next few years," Reid continued.  "The US is now no longer the world’s sole economic superpower and indeed  its share of world output (on a PPP basis) has slipped below the 20%  level which we have seen was a useful sign historically of a single  dominant economic superpower. In economic terms we already live in a  bi-polar world. Between them the US and China today control over a third  of world output (on a PPP basis)."
 
 Reid offered this prescient quote from Napoleon Bonaparte: "Let  China sleep, for when she awakes, she will shake the world."