“It makes no sense,” Ms. Dunphy said. “You had the president and others saying that the intent was to add 20 weeks of benefits, and now we have this glitch.”

For people suffering long-term unemployment, a gap of several weeks in aid  let alone a premature, permanent end  can be cataclysmic. Alexandra Jarrin, 48, was laid off in March 2008 from her job in New York as a director of client services. As she searched widely for a job, moving back and forth between New York and Tennessee, she received aid of more than $400 a week that, she said, just barely “kept my head at the waterline.”

But her extensions ran out early last month and in subsequent weeks, as Congress deliberated, her life fell apart. She has just started receiving what will be 14 extra weeks of aid under the new law, but faces eviction from her apartment in Brentwood, Tenn. “There’s no way I can recover now, I’m too far behind,” she said.

Image Standing in line at a job fair sponsored by Monster.com in New York City earlier this month. Credit... Spencer Platt/Getty Images

In ordinary times, unemployed workers in most states receive 26 weeks of benefits, averaging just over $300 a week, paid from state insurance funds. Many find jobs before exhausting the aid, but unemployment has been particularly tenacious in the current recession and recovery. Under temporary measures, workers are currently eligible for a series of federally paid extensions, awarded in stages often lasting 13 or 14 weeks at a time.

Some nine million people now receive unemployment benefits, five million on the initial state programs and four million through federal extensions.

Without renewal of the programs for 2010, at the turn of the year recipients will continue receiving benefits to the end of their current stage but will no longer jump to the next stage. Thus Ms. Jarrin, if she fails to find work, will finish out the new 14-week period but will not receive the additional six weeks that Congress promised. She said she had sent out 2,000 résumés and had only a handful of interviews, without success.