A good way to do it would be to radically downsize the federal government and return back to limited constitutional government. The less money they have, the less stuff they can do. Return power (and tax revenues) back to the states so that the people of that state can have a more powerful influence in state/local politics instead of everyone pleading, fighting, and begging at the national level in Washington.

And since radical downsizing won't happen voluntarily, as both political parties are corrupt and incompetent, the only way I can see this happening is for the government to continue borrowing and spending money into oblivion, which will ultimately trigger an economic default. At that point, there will be no money for new secret programs.