It looks like the Obama administration’s projected cumulative budget deficit of $7 trillion over the next 10 years will need substantial revision.

The L. A. Times reports that the non-partisan Congressional Budget Office is expected to announce their estimate today, and it is believed to be $8.6 trillion. With so-called “fiscally conservative Democrats” already rebelling over the size of the deficit increase, this can’t be good news.

Where Obama’s budget foresees rolling up $7 trillion in cumulative deficits over the next 10 years, Sen. Kent Conrad (D-N.D.) on Thursday pegged the deficits at $1.6 trillion higher over that period.

Conrad, chairman of the Senate Budget Committee, said the figure was calculated by his panel’s Democratic staff members.

The Congressional Budget Office report today is expected to reflect a worsening deficit outlook in part because economic conditions have deteriorated in the two months since the administration set its budget assumptions. The office is expected to project lower revenue and higher spending than what Obama’s budget assumed.

Sen. Ben Nelson (D-Neb.), one of about 15 moderate Democrats concerned about Obama’s spending levels, said the White House might have to reassess its priorities in light of the new estimates.

Meanwhile, this kind of response may not strike the right political tone:

“It’s not productive to constantly be chasing your tail and, as things change every day, revise your numbers,” said Kenneth Baer of Obama’s budget office.

To dismiss an increase of $1.6 trillion — which represents more than 20% — so lightly is both arrogant and tone deaf. Not the exactly the win-friends-and-influence-people style the White House advertises itself as being committed to.

Besides, someone should ask Kenneth Baer: if it isn’t time to revise your numbers when they’ve changed by more than 20%, then what’s the right threshold?