The difference comes from the starting point. Democrats are working off of the president's requested budget for the fiscal year, which was $1.128 trillion. That's the same baseline that House Republicans used when they cut $102 billion with their first bill, H.R. 1, bringing the spending down to $1.026 trillion.
But House Republicans are no longer using the president's request as their baseline and instead are using the spending level that existed on January 1. For obscure accounting reasons, there's some dispute about whether that number is $1.087 trillion or $1.089 trillion.
There have been two stop-gap spending bills since the GOP took over the House, both of which extracted cuts, bringing the number down to $1.077 trillion.
Democrats have now agreed to bring the number down to $1.050 trillion, which is either a cut of $78 billion (from the president's requested budget) or $37 or $39 billion (from the Jan. 1 baseline) or $27 billion (from the current baseline).
There are games being played on both sides: The president's request was never going to be enacted into law, so both parties have been disingenuous in using it as a baseline. But there is a number that realistically could have become law, and that's the one that was proposed by Sens. Jeff Sessions (R-Ala.) and Claire McCaskill (D-Mo.). Known as the Sessions-McCaskill level, it blew up in December over a fight over earmarks, but it had the broad support of both parties in general.
That figure was $1.108 trillion -- $58 billion above what Democrats are now willing to accept.
So while Republicans have managed to extract roughly $39 billion from current levels, the more impressive feat from their perspective is to have won $58 billion in cuts from what was broadly politically acceptable only three months ago.
Two things to keep in mind: Neither party is saying what will be cut, and on MSNBC's Dylan Ratigan show Friday afternoon, House Assistant Democratic Leader Jim Clyburn (D-S.C.) said that he would support Speaker John Boehner's decision not to tell the American people what is being cut so that "special interests" don't have the chance to fight back.
And the fiscal year is roughly half over and the government has been operating at the current spending level up until now, meaning that the $39 billion in one-year cuts will need to be made in just half a year -- effectively doubling their impact. The focus on Planned Parenthood may be distracting from a dramatic GOP victory on spending.