Depends on what problem your solving. If you want the oldest 10% of the population not to die in poverty that's actually fairly easy to solve. In you want ~0.00% deaths from starvation that's also easy to solve. However it's cheaper to provide basic heathcare to everyone than it is to provide top quality heathcare to the elderly.
Reducing drug use to some significantly lower level is very possible, ending it is not. Going to Mars is easy, colonizing Mars is a pipe dream. Governments can solve a wide range of problems reasonably efficiently, but open ended goals without a clear stopping point become unbound problems.
