It's not so much what they've done, it's what they haven't done. The economic crisis is creating enormous problems in many parts of the country and the people don't see Congress doing anything about it:

Americans' assessment of Congress has hit a new low, with 13% saying they approve of the way Congress is handling its job. The 83% disapproval rating is also the worst Gallup has measured in more than 30 years of tracking congressional job performance.

The prior low approval rating for Congress was 14% in July 2008 when the United States was dealing with record-high gas prices and the economy was in recession.

The current results are based on a Dec. 10-12 Gallup poll, conducted as Congress is finishing work on an important lame-duck session. The session has been highlighted by the agreement on taxes forged last week by President Obama and Republicans in Congress. The tax deal preserves the 2001 and 2003 income tax rates for all Americans for two years, revises the estate tax, extends unemployment benefits for the long-term unemployed for a year, and reduces payroll taxes for American workers. It is expected to pass despite vocal opposition from some lawmakers.

Surprisingly, Gallup states that these numbers do not reflect any feelings against Democrats as a result of last month's election:

Frustration with the tax deal among Democrats in the general population could be a major reason for Americans' historically low approval rating of Congress. That frustration could be opposition to the bill's particulars or frustration with the Democrats in Congress opposing the president's deal. Democrats' approval of Congress is down significantly, to 16% now, from 29% in November. The November poll was conducted after Republicans won control of the House of Representatives for 2011-2012 in the midterm elections, so the drop in this month's numbers is not a reaction to the Democrats' midterm losses.

Meanwhile, independents' and Republicans' ratings of Congress are down similar to November.

It remains to be seen if the GOP can raise those numbers significantly. Since the Dems will do all in their power to obstruct, it seems unlikely.