"The money and the lobbying power is stacked against us," said a representative of NumbersUSA. "This is an issue that people see and experience the effects of on an everyday basis. There is definitely a very powerful grass-roots activism on this issue."

NumbersUSA has more than 300,000 activists sending faxes and calling Congress, an increase from 100,000 two years ago. More than 1 million people receive e-mail alerts from the group.