Reporting from Washington — After the House approved the largest federal spending reductions in decades, Americans on the losing end have awakened to the ramifications of deep cuts in programs and are beginning a nationwide backlash as Congress works to stave off a potential government shutdown.

In at least 10 states, mothers with toddlers in tow protested the potential loss of Head Start preschools, which could be forced to cut enrollment by 200,000. Sheriffs appealed for the continuation of law enforcement assistance. Newspaper ads, letters and Internet appeals warned the cuts could hurt large groups of vulnerable Americans.

Job counselors said they would be powerless to train 14 million Americans still out of work. Mayors and other local elected officials were fighting to save programs that would build infrastructure and care for their most vulnerable citizens.