We got the most thunderous Just-In-Time monetary policy today that is a substitute for the absence of any degree of stimulative fiscal policy.

FORBES: QE4 is Just-In-Time Fed Policy to Avoid Calamity

In retirement, benefits payable from the personal accounts would substitute for a portion of Social Security benefits based on the degree to which workers exercised the account option over their careers.

FORBES: Newt Gingrich's Entitlement Reform Plan

It produces less carbon dioxide for a unit of energy than coal or oil, so the climate will benefit to the degree that gas replaces either of those: it will mostly substitute for coal, though some oil too, especially if gas-powered trucking becomes widespread.

ECONOMIST: Natural gas