The federal government consumes 25% of GDP. Traditionally the government per GDP was 20%. Obama increased this to the 25% in his first year and continues at this pace of consumption.
China doesn't subsidize the US government anymore. It has been selling off it’s exposure to US debt. That is why the Fed has been continuing with QE 3. It is the Fed who is buying US Treasuries.
The Fed continues to feed the beast by inflating the money supply.