Why do Obama and Boehner want to get a debt deal done before the market opens?

I was just reading an article saying that Obama and Boehner want to get a debt deal done before the markets open Monday. Granted, the past few weeks on Monday there's been a huge sell-off, but it's rebounded every time. How would this time be any different?Why do Obama and Boehner want to get a debt deal done before the market opens?Because the longer it takes to get the deal done, the more likely it is that credit rating agencies will downgrade the current AAA credit rating the US has. If that happens, the market will tank a ton and borrowing costs will go up. In addition, it will take a while to write any agreement into law.Why do Obama and Boehner want to get a debt deal done before the market opens?So that the markets don't crash.