(1) Spending money on wasteful harmful shit, i.e. warfare (DoD, CIA, etc.), police state (FBI, NSA, etc.), drug war (DEA, etc.), etc.
Are you suggesting the US just eliminate these organizations or that politicians should adjust their directives through policy and doctrine? Because if it's the latter, then you're likely not going to affect any real savings as a percentage of the budget.
(2) Permitting the financial industry to extract such insane rents on everything by not regulating them.
I'm in the financial industry, neck deep in it, and we operate under oppressively redundant regulations; the cost of which we pass on to our clients who pass them on to you and the federal government through tax deductions. The problem is that regulations were written to benefit the largest and most politically influential banks.
In fact, Mitt Romney discusses this scenario very elegantly in his book. Too bad more people didn't read it, as this election will really have some consequences.
(3) Subsidizing established industries, especially oil, nuclear, and agricultural subsidies.
Solar energy subsidies dwarf the above by near orders of magnitude. Do you think those subsidies should cease as well?
We could cut taxes by massive amounts if we halted all that waste, corruption, and exploitation.
We could do the above for the common good, but it is not enough *significantly* cut taxes. To do that would require cutting or eliminating entitlement spending. And besides, once a tax is levied, the imperative is to spend that money, not return it.
The Christian religion has been and still is the principal enemy of moral progress in the world. -- Bertrand Russell
Apparently Bertrand Russell was a fool. Who knew?