When Does Federal Deficit Spending Stop?

It looks like the Senate is going to extend the "cash for clunkers" program. They spent $1 billion so far and now are going to add another $2 bills. It's shocking that this is now considered such a low amount. Hey, only $3 billion total! We got away cheap today.

At what point does the Obama administration and Congress feel that they're spending too much money? Do they have an arbitrary number they might reach where they say, ok we won't spend another trillion or hundred billion or whatever else this year? I realize federal budgeting is not exactly like personal budgeting since I can't double my spending and than just print more money for myself or tax others to get the extra income I need to support my extra spending. But still. Doesn't there come a point when somebody in charge becomes seriously concerned about the spending? Just curious.