In California, Head Start has been especially beneficial to Latino and other limited-English speaking families, offering preschoolers from low-income households preparation for Kindergarten.
President Lyndon B. Johnson launched it in 1965 and supporters have touted its success.
"Without it, I'm afraid we're going to have a lot of kids who are missing out on a critical year in their development," California Head Start Assn. Rick Mockler said.
Early childhood educators are worried about California losing more than 5,600 Head Start slots. They say the number of words a child knows when they start Kindergarten is a marker for future success.
"We're taking families that are highly vulnerable, and we're cutting them loose with these cuts," Mockler said.
These families can't simply go to other pre-school programs.
During the recession, California eliminated 100,000 slots there.
Things, though, are slowly improving. The Legislature approved $25 million more for pre-school programs this year, giving priority to kids who would have normally gone to Head Start.
But Head Start supporters say the other programs are not as effective in dealing with at-risk kids.
"That's the irony of sequester, we're removing funding for programs that we know work and that prevent outlying costs to health, and the economy, and graduation rates and prison rates," Western Center on Law & Poverty spokesperson Jessica Bartholow said.
The timing, too, couldn't have been worse.
With an improving economy, people are starting to find jobs again, which means more families are needing Head Start.
"We know that a lot of the jobs people are returning back to are low-income jobs and so they're less able to afford childcare and pre-school on their own," Bartholow said.
Thousands of struggling families will now have to make a choice of staying home or leaving their pre-schooler somewhere that isn't as good as Head Start.