It is often said the the President of the United States is the de facto leader of the world. If that's true, then world leadership has its limits. I am not going to list all the limits of the U.S. President's power here -- just President Barack Obama's inability to halt the use of taxpayer money to pay $200 million more in bonuses to American International Group (AIG). So far, taxpayers have invested $182.5 billion for a 77.9 percent stake in the company. Though it is clearly winning this face-off, AIG may be fronting for the even more powerful Goldman Sachs Group (GS). Will Obama draw a line in the sand or let AIG defeat him?