The target: $100 billion. Saved from the budget ax: military, domestic security, and vets.

Everything else is on the table. And since we are talking about discretionary spending, we're looking at some programs getting cut back 20%.

The reductions that would be required in the remaining federal programs, including education and transportation, would be so deep - roughly 20 percent on average - that Senate Republicans have not joined the $100 billion pledge that House Republicans, led by the incoming speaker, Representative John A. Boehner, made to voters before November's midterm elections.

Even if adopted by the House, the Republicans' budget is unlikely to be enacted in anything like the scale they envision, since Democrats retain a majority in the Senate and President Obama could veto annual appropriations bills making the reductions.

But the effort is more than symbolic: in particular it could give House Republicans increased leverage in budget negotiations with the White House this winter and spring, when the administration must get Congress to raise the federal debt limit or risk a government financing crisis.

The budget-cutting exercise is perhaps the biggest test facing the House Republicans as they seek to remain united and to keep faith with Tea Party members, many of whom remain suspicious of the party's willingness to vote for deep spending cuts.

OK - so they won't get $100 billion cut from the budget. But if they get $75 billion it will be a huge victory. That's the advantage of starting from a large baseline of cuts.

And don't forget that the GOP is starting from a hugely bloated budget to begin with. Education spending alone has gone up 60% since Obama took office. This is why I think they are going to get a lot closer to cutting a significant amount than some analysts might think.

Update:

It appears that $100 billion number was unrealistic given the realities of where we are in the fiscal year (not to mention opposition from senate dems and Obama). The GOP is walking back from that number:

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.

"House Republicans will continue to work to reduce spending for the final six months of this fiscal year - bringing nonsecurity discretionary spending back to pre-stimulus, pre-bailout levels - yielding taxpayers significant savings and starting a new era of cost cutting in Washington," said Conor Sweeney, communications director for Mr. Ryan.

It would be wrong to see this as a betrayal. The reality of the budget mess we're in is that it is going to take many years, with ups and downs, victories and defeats, before we return to fiscal sanity. The key for the GOP will be to keep their eyes on the prize and not be deterred or scared off from attacking the problem.

At the moment, this is the best they can hope for.