So the deal for the "largest spending cut in history" that no one knew the components of until ~5 minutes ago is coming up for rubber-stamping today, to avoid a government shutdown. The votes are expected to be there. But maybe we'll get lucky and the government of the greatest nation in the history of the world will shut down anyway, over confusing math.

House Republicans were shocked to see a report last night about how this $38 billion in cuts actually only reduced expected 2011 outlays by $350 million. Boehner was pulling their leg! Well, not really. Here's the simplest explanation for the difference in bottom-line numbers, from TPM: "As advertised, when the House and Senate pass the spending bill this afternoon, domestic discretionary appropriations will fall $38 billion from levels set at the beginning of the year. But because some of the cuts will be realized over years, and because some of the savings are culled from left-over money in existing accounts, the bill will only reduce direct spending by about $350 million." If you're really into budget porn and want to see the calculation of cut-to-outlay ratios, visit David Rogers in Politico.

Anyway, all of this math is confusing, and ultimately angering, influential Tea Party opinionistas who were promised $100 trillion in cuts every second of every day from the moment the Republicans took power. Will this "new math" damage the bill's chances of passing the Republican House today? If so, Minority Leader Nancy Pelosi has pledged to step in:

If Republicans defect in larger-than-expected numbers, Democrats will be called upon to ride to the rescue, to avoid a government shutdown.

That will give Pelosi some behind-the-scenes leverage with Boehner — after all, passing this bill is not her responsibility. "I feel no ownership of that or any responsibility to it," she said.

But she suggested strongly that Democratic votes will be there if needed. "This is about keeping government open," she said.

Oh, how she would savor being called in to rescue John Boehner.

[Image via AP]