A special congressional committee charged with finding a way to trim the federal deficit by at least $1.2 trillion over the next decade, has conceded that it cannot agree on a plan to reach that goal.

That acknowledgment will trigger $1.2 trillion in mandatory across-the-board cuts starting in January 2013, half from defense and half from nondefense categories, including construction programs—unless Congress passes a new law to modify or abolish them.

President Obama called on Congress to come up with a "balanced plan"--presumably including some tax increases--to narrow the deficit by at least $1.2 trillion, but vowed to veto legislation that would simply undo the cuts or selectively restructure  them.

If the cuts stay in effect, construction programs, many of which already have absorbed reductions this year, will take further hits over the next 10 years.

The formal announcement of the Joint Select Committee on Deficit Reduction’s failure to strike a deal had been widely predicted in recent days and came Nov. 21 in a late afternoon statement by its co-chairs, Sen. Patty Murray (D-Wash.) and Rep. Jeb Hensarling (R-Texas).

“After months of hard work and intense deliberations,” Murray and Hensarling said, “we have come to the conclusion today that it will not be possible to make any bipartisan agreement available to the public before the committee’s deadline.”

The 12 members of the so-called “supercommittee” included six Democrats and six Republicans, half from the Senate and half from the House.

The Budget Control Act, signed into law on Aug. 2, created the panel, gave it its mission and spelled out the fallback program of mandatory cuts.

That measure also set a Nov. 23 deadline for agreeing on a deficit-reduction plan, committee would have had to have a deal 48 hours earlier for congressional procedural reasons.