Everybody, anywhere on the political spectrum, says that the economy sucks because business investment is low. Business investment is low because the economy sucks SO MUCH that cash is an appealing investment, because it is 100% sure not to lose value at any less than the rate of inflation (this is the heart of a liquidity trap). If we make cash a less appealing investment by raising the rate of inflation, businesses will invest more in the economy.
There it is, my 3 sentence argument for targeting an inflation rate of 5% instead of 2%.
Side benefit of raising the inflation rate? Every pre-existing mortgage becomes more affordable, every pre-existing car payment becomes more affordable, every pre-existing student loan becomes more affordable, and wealth is transfered from the big guys who have the cash, to the little guys who owe money.