Charles Krauthammer and Greg Sargent are fighting today over a point in Paul Ryan’s budget projections. Krauthammer complains that President Obama contends that:

Paul Ryan’s budget would cut Pell Grants by $1,000 each, if his domestic cuts were evenly distributed. (They are not evenly distributed, making the charge a fabrication. But a great applause line.)

Sargent responds:

The White House is assuming even distribution of those cuts because Ryan’s budget itself has not told us in any meaningful detail what it would actually cut to realize spending-reduction targets.

He further argues that Ryan and the Republicans are running a shell game, in which they want credit for large general-spending cuts while denying that they will cut any particular popular program.

The real truth of this debate? Imagine two kids fighting about who knocked over the sand castle . . . in the shadow of a huge wave about to break and wipe out the entire beach.

No, that wave isn’t the budget deficit. It’s the actual deficit reduction in the Ryan budget, which is found in the long-term plans. Specifically, by 2050 Ryan would set the entire federal budget other than Social Security, Medicare, Medicaid and CHIP (and interest on the debt) to 3.75 percent of GDP. That figure would include defense spending, which Republicans generally want to keep at around 4 percent of GDP.

At best, if defense spending slows to match the postwar low of 3 percent of GDP, Ryan would still leave less than 1 percent of GDP for the rest of the federal government. In other words, either Ryan’s deficit reduction is a sham, or Ryan — and the House Republicans who voted with him, and Mitt Romney, who said he supported Ryan’s plan — would shut down pretty much the whole government.

So forget about whether Ryan would cut Pell Grants a little or, perhaps, would instead cut some other, less popular program; the reality is that his budget would eliminate all Pell Grants, along with the rest of federal education spending, the national parks, highway spending, veterans’ programs, and, well, pretty much everything else the federal government does.

That’s what House Republicans voted for. What Krauthammer and Sargent are arguing about is only which programs would be shut down first.

I know a lot of liberals have been knocking Ryan for cutting taxes on the rich while slashing programs for the poor, but in my view that mistakes the situation; Ryan is promising to shut down, with a few exceptions, the entire federal government. That’s what’s worth talking about, not the comparatively small (although still substantively quite devastating) 10-year projections.

If you want a balanced budget and don’t want to defend eliminating the federal government, you shouldn’t be out there defending Ryan — and the truth is that Ryan just isn’t serious.