Their excuse will be that the fiscal year, which began on October 1, will already be almost half over by the time the budgetary resolution that was passed during the lame duck runs out in March. That means they’ll only have seven months to work with this fiscal year; when they said they’d cut $100 billion, they meant the first full fiscal year that they’re in charge. But wait, you say! Shouldn’t it be fairly easy to find $100 billion to cut in an annual budget that exceeds $3.5 trillion? Well, yes — except that the GOP’s limiting itself to cutting discretionary spending (Social Security and Medicare are, as ever, completely off-limits) and even within discretionary spending they refuse to touch “security” budgets, i.e. Defense and Homeland Security. That leaves just $500 billion or so for this year to play with, and since, as Rich Lowry noted earlier at the Corner, a good chunk of that will already have been spent by the time the continuing resolution expires in the spring, they’d have to make huge cuts to what’s left in order to get to $100 billion in savings overall.

The point to ponder here, I think, is that even the highly touted $100 billion figure is just a small fraction of last year’s deficit. Even with a tea-party Congress, even with a gigantic pool of expenditures to cut from, political reality is such that not only can’t they reach that modest, largely symbolic target in seven months, they’ll actually have to move heaven and earth during the next full fiscal year to get Obama and the Senate Democrats to agree to it. This is what we’ve been reduced to — the suspense of wondering whether the new Republican majority can achieve cuts that will barely make a dent in our annual budget shortfall. Hugely depressing.

Now aides say that the $100 billion figure was hypothetical, and that the objective is to get annual spending for programs other than those for the military, veterans and domestic security back to the levels of 2008, before Democrats approved stimulus spending to end the recession.

Yet “A Pledge to America,” the manifesto House Republicans published last September , included the promise, “We will roll back government spending to pre-stimulus, pre-bailout levels, saving us at least $100 billion in the first year alone.”

Republican leaders have repeatedly invoked the number. On Tuesday the Web site for Representative John A. Boehner, the incoming House speaker, included a link to his national radio address on the Saturday before the midterm elections, in which he said, “We’re ready to cut spending to pre-stimulus, pre-bailout levels, saving roughly $100 billion almost immediately.”…

On Tuesday, aides to Mr. Ryan and Mr. Boehner blamed Democrats’ failure to pass the regular appropriations bills for fiscal year 2011 for forcing Republicans to reduce their goal to perhaps $50 billion to $60 billion.

Actually, maybe I have the spin here wrong. I thought the excuse would be “we don’t have enough time to cut that much this year,” but that bit about $100 billion being “hypothetical” makes me wonder if they’re prepared to back away from it next year too. They wouldn’t dare do that with tea partiers watching them anxiously. Would they? Brian Riedl, the lead budget analyst for the Heritage Foundation, told Newsmax in November, “The Republican leadership has committed to this $100 billion cut… I expect them to do everything in their power to enact it. They’re on the record, they ran on this, and if it’s brushed aside there would be harsh political consequences.” Well, they’re sort of brushing it aside now, albeit with the caveat that they won’t have a full year yet to live up to their promise. (Never mind the fact, noted by the Times, that having less than a full fiscal year to deliver was entirely foreseeable when they were touting the $100 billion number.) Are there political consequences for that?

In fact, according to The Hill, not only can’t they find enough cuts to hit the $100 billion target before the fiscal year runs out, they might not even have time before March to put together the 12 different appropriations bills they’d need to make targeted cuts. There are “only” 43 legislative days before then, only 23 of which are scheduled to be spent in session; the House could, as an alternative, pass a continuing resolution of its own cutting spending for the rest of the year by $100 billion and leaving it to Obama to figure out where the cuts should come from, but that’ll almost certainly never pass the Senate. Exit question: What now?