We already have.Bush's TARP was about $1T. Obama added almost another $5T in self-stimulation. Neither worked. They simply gave the very people that failed to behave responsibly a get out of jail free card. Among these include the bankers, the people that bought homes as items of speculation, and people living far beyond their means.
How much more shall we spend before folks on your side of the political divide finally admit it does not work?
BTW, what neither your side nor most so-called conservatives get it that what Obama did was NOT Keynesian. It was far worse. A Keynes stimulus would have gone directly into the economy in the form of jobs for the masses. Obama self-stimulation was designed to benefit his favored oligarchs and low rent voter base but it produces no jobs of any note outside the wretched public sector. Now Keynes was wrong on many levels, but Obama's actions are pure political megalomania trying to get people to like him.