(CNN) -- For many families, the nation's lurch toward the so-called fiscal cliff evokes either mind-numbing confusion, measured optimism or downright fear.
But for Lisa Slifer, a single mother of three, the consequences of failing to come to a deal are all too real.
Slifer's son, Kara, 11, is autistic. He and his mother depend heavily on state, local and private programs that receive grants from Washington. Many of those funds could be cut back if Congress and the White House can't avoid the automatic and drastic spending cuts that kick in less than three weeks from now.
For instance, without a $3,000 grant Slifer received from Penn-Marr Human Services, a non-profit agency in her home state of Maryland that supports families and individuals with disabilities, she would not have been able to put a fence around her yard so that Kara, who has problems sitting still, would not wander off.
She gets support from another state program that helps pay for a private school for Kara that specializes in helping children with special needs. And she is on a waiting list for another grant that would help cover the $300 per week she is spending for respite care for her son, run by a pastor and his wife who have a special needs child. All of these services are funded directly or indirectly through federal dollars.
Slifer, who works as a government contractor in international development, worries that no deal on Capitol Hill could mean support services for Kara and other children with special needs will dwindle or disappear.
"I don't think we would be able to basically afford the kind of services that we have for him now at home and then there's the emotional consequence of that," said Slifer, adding that her worse fear is not being able to provide what's needed to keep Kara living at home and out of an institution.
"You have people around you who really understand your child and are really willing to support you and support you in keeping your child at home, and so the thought that some of that would go away and that we would have a difficult time maintaining him at home is probably the most devastating thing," she said.
No deal could mean across-the-board cuts for most federal agencies, including the Office of Special Education and Rehabilitation Services, which had a $16.36 billion budget in 2012. It's parent agency, the Department of Education, has a 2013 budget request of about $68 billion, which would be subject to a massive cut if a budget deal is not reached by the January 1 deadline.
And cuts like those trickle down to the state level.
This fiscal year, Maryland, where Lisa lives, received more than $300 million in federal funds for programs for special needs children. The Maryland State Board of Education said about 113,000 students depend on those funds.
Maryland Gov. Martin O'Malley's office told CNN that drastic cuts could mean less access to medical, psychological and counseling services as well as job training for special needs students.
Anne Stauffer of the Pew Center on the States said that the top five grants that would be subject to sequester -- or the automatic budget cuts -- include Title One grants to local education agencies that are targeted for low-income children and special needs children. Other programs that receive federal assistance -- education grants, Head Start, nutrition programs for low-income women and children and public housing -- would also likely be cut.
"Those are basically the largest grants that go to states with the largest amount of money at stake," she said.
But there are some on both sides who appear not to be as worried if the deadline passes and the country slides over the fiscal cliff.
Liberal columnist Paul Krugman argued in the New York Times that lawmakers should "just say no, and go over the cliff if necessary."
"It's worth pointing out that the fiscal cliff isn't really a cliff," Krugman wrote. "Nothing very bad will happen to the economy if agreement isn't reached until a few weeks or even a few months into 2013."
Former Republican presidential candidate and Speaker of the House Newt Gingrich, a leading voice on the conservative side, wrote in a blog post that "Every time you hear 'fiscal cliff,' just remember it is an artificial invention of the Left ... a mythical threat which can only be solved by Republicans surrendering their principles and abandoning their allies."
Still, Slifer said it's frustrating to watch lawmakers posturing, unable to reach a compromise.
"It's almost as if they're not taking into account the stresses that middle income families are going through right now," she said. "I think that's really the most terrifying thing for us."