A special congressional committee created to try to curb the national debt abandoned its work and conceded failure Monday, the latest setback in a long effort by Washington to overcome ideological differences and stem the rising tide of red ink. In a joint statement issued hours before a midnight deadline, the Democratic and Republican leaders of the panel said that they were “deeply disappointed” by their inability to reach an agreement and that they hope for progress in the months ahead. The breakdown left the nation facing the prospect of automatic reductions to government agency budgets in January 2013.