If Congress can't find a better way to cut $85 billion from the budget this week, automatic cuts kick in on Friday.
The Transportation Department warns it would have to furlough hundreds of air traffic controllers.
"Safety will not be compromised, but we will have to work with the airlines in slowing planes down," explained Transportation Secretary Ray LaHood.
The White House says 10,000 teachers could lose their jobs and food safety inspections would be scaled back.
"This is something that nobody wants. It's not a balanced, thoughtful compromise," says Colorado Governor John Hickenlooper.
Oklahoma Republican Senator Tom Coburn, meanwhile, says the White House is exaggerating, and painful or not the cuts must happen.
Politically, some analysts think Republicans have more to lose.
"The more people see services disrupted, just as you would in a government shutdown which is more dramatic, the more likely it is you'll get Republicans to bend," says CNBC Chief Washington Correspondent John Harwood.
Right now there's no sense if any serious compromise is in the works, with just four days left and counting.