Unless Congress extends emergency unemployment insurance before December 28th the benefits will expire for 1.3 million Americans and another 800,000 over the next few months. The emergency unemployment insurance has been in effect since late 2008. If these benefits are allowed to lapse the U.S. unemployment rate may decrease by between 0.25% and 0.5% because the most likely scenario for the 2.1 million people is that they will drop out of the labor market and stop looking for work. There about 4.1 million people in the U.S. that have been out of work for more than 27 weeks. Research has shown that the longer a person has been out of work the less likely it is that they will be able to return to full employment.
See "Unemployment benefits will soon expire for 1.3 million workers. Where will they go?", Brad Plumer, The Washington Post, December 2, 2013