Scott Sumner writes,

In my view, Japan is the future of the global economy. Not the deflation (I think the Fed will be able to keep inflation close to 2%) but the low real interest rates. In retrospect the 2001 recession (when rates fell to 1%) was the canary in the coal mine. Nominal rates will probably be unusually low from this point forward. Global saving will increase dramatically as Asian countries get richer (remember that most people are Asians) and slowing population growth outside of Africa will dramatically reduce the demand for investment funds.

It is not S=I. It is S = I + (G-T), and the equilibrium interest rate is rather high. Just wait.