Though Bruce Barteltt and Rep. Justin Amash are heading along different trajectories in their views about the size of government and taxes, they converge on a key criticism of Rep. Paul Ryan’s 2013 budget — the numbers just don’t crunch. As Bartlett writes at the Fiscal Times, “Any tax reform plan that simply asserts it will collect a certain percentage of GDP in revenues while specifying the rate structure but not defining the tax base is fundamentally dishonest, in my opinion. The CBO was simply ordered to assume that Ryan’s numbers are legitimate.” Given the budget’s vague assumptions and unrealistic ambitions for and cutting spending and recouping revenue from tax-code restructuring, Bartlett concludes, “the Ryan budget should be seen as nothing more than a PR document for Republicans so they can say they have a plan to balance the budget, cut taxes, and cure the common cold.”

Amash, writing on his Facebook page, is more generous to his colleague — “I have a lot of respect for Chairman Paul Ryan and his outstanding staff” — but is also troubled by assumptions behind the plan, as well as its failure to address military spending and live up to the requirements of the Budget Control Act:

Today’s committee vote was one of the most difficult of my life. Ultimately, I voted “no” for a few basic reasons: (1) The time to balance is too long. According to CBO, the budget won’t reach balance until nearly 2040. Under an alternative growth scenario, it still might be unbalanced until the mid-2020s. (2) The budget exempts military spending from reductions, which makes it more difficult to achieve bipartisan support to reform the primary components of our annual deficit: Social Security, Medicare, and Medicaid. (3) The FY 2013 cuts do not appear to match the magnitude of the cuts required under the post-sequester Budget Control Act, which most Republicans and Democrats agreed to in exchange for raising the debt ceiling. I did not support the BCA (raising the debt ceiling) because I believed the parties were making a political compromise—promising future cuts that would not happen—rather than a genuine compromise to deal with the debt immediately.

Reason‘s Nick Gillespie, appearing on Fox News, is also unimpressed: