As many as 1 million Americans will stop receiving food stamps over the course of this year beginning on Friday, the consequence of a controversial work mandate that has been reinstated in 22 states as the economy improves.

The 20-year-old rule — which was suspended in many states during the economic recession — requires that adults without children or disabilities must have a job in order to receive food stamps through the Supplemental Nutrition Assistance Program for more than three months, with some exceptions. Many states have begun to reimpose the federal rule as the economy recovers, with the largest group reviving it at the beginning of this year. As a result, many recipients' three-month limit expires today, April 1.

The change has reignited a fierce debate between conservative leaders, who say waiving the mandate discourages people from working, and their liberal counterparts, who say the three-month time limit ignores the reality that jobs are still hard to come by for low-skilled workers.