*Jon Henke calls for Line-Item Budgeting – not just a line-item veto by the president, but forcing Congress to vote on each expenditure. More here. There would obviously be some practical hurdles: how do you decide what is a separate item? For example, can the Army budget include tanks and guns in the same item? One could see how even the hardiest advocate of creating obstacles to government spending might blanch at this if it’s not carefully crafted, even leaving aside the practical poilitical obstacles to either (1) amending the constitution to require this or (2) getting our legislators to agree to it, to the detriment of their own influence.
A similar problem besets two similar ideas I keep coming back to. One is the idea of some sort of prohibition on items of spending and taxation that are, in effect, special-interest legislation. I do think you could, if you were writing this all from scratch, devise a fairly clear test for expenditures and tax breaks that do not benefit the general public, and perhaps even use the courts to enforce that line. But there would still be problems in policing the marginal cases.
Similarly, my other idea, which would require a narrow exception for certain critical national security functions: prohibit the federal government from sending money to state and local governments, or from imposing most mandates on them. Each governmental entity should raise through taxation whatever it needs, and no more than it can justify to the voters in its own jurisdiction.