With ObamaCare already set to squeeze medical providers, the health side of the budget may be largely "off limits" in finding near-term budget savings, said Josh Gordon, policy director at the budget watchdog Concord Coalition.

With major short-term changes unlikely in Social Security, the brunt of the budget heavy lifting would fall on the discretionary budget and tax policy — "probably more on the tax side" — Gordon said.

But in addition to ObamaCare taxes, Bush-era income tax cuts on the wealthy will expire at year-end.

Any budget deal will require broad bipartisan support, and budget specialists see limited chance of that arising any time soon in the wake of partisan warfare over health care reform.

"Right now, the two parties are diverging instead of converging," Gordon said.