Q. Who permits government whatever it does?

The simple answer can be: people in a democracy and the monarch/dictator in a monarchy/dictatorship. But neither monarchy exists in its original form nor does a dictator/despot/autocrat work without a coterie around. Some people always participate in the decision-making process, deliberate on the issues and implications, and clinch the matter following certain rules given from outside (say, by the constitution) or decided in the process itself, which is itself a decision-making process. How individual preferences get translated in public choice over a public issue is broadly the area of Public Choice.