Ezra Klein -The market isn’t totally wrong, of course. The federal government probably won’t default on its debt. But it’s actually pretty hard to explain how we get the spending line and the revenues line to match each other. And we have a really dysfunctional political system. We’ll figure it out somehow. We always do. But our low borrowing costs are an advantage we want to preserve for as long as possible. That means keeping the market from realizing that partisan polarization mixed with our weird legislative system makes insane outcomes easily imaginable.
This is why a shutdown would be so dangerous. A last-minute deal tells the market that America is a country that dithers and procrastinates and anguishes but eventually makes the necessary decisions to avert terrible consequences. We can be trusted to follow through, even if only at the last minute. A shutdown tells the market that our political system has become so dysfunctional that we actually can’t be trusted.
http://www.washingtonpost.com/blogs/ezra-klein