Of course, Witcover being liberal would never point out that reductions in both future spending plans and actual current spending would wipe out most of this "dark hole".
Basic Republicn Strategy: Reduce taxes, thus leaving less money available for government to spend, thus constraining the growth of spending (and that of government).
Basic Democrat Strategy: Increase spending as much as possible, beyond the inflation rate and population growth, redistributing wealth to obtain votes. Then complain loudly when tax revenues fall (as they inevitably do, riding the business cycle) -- starving children, no water to put out forest fires, etc. -- and demagouge the Republicans until they agree to the "necessary" tax increases.
In this tug-o-war, the latter scenario occurs far more frequently than the former.
Have a nice day.