The best illustration of that impact comes courtesy of Republican pollster Bill McInturff whose analysis of the political and economic impact of the last debt ceiling fight was seminal stuff. (Read Bill's entire PowerPoint presentation here.)
Using the Michigan Consumer Sentiment Index as a broad -- and historically reliable -- measure of consumer confidence, McInturff compared the drop in the index during the 2011 debt ceiling fight to other catastrophic events in history.
Here's his slide:
The slide speaks for itself. The last time the government came close to defaulting on its debt, the impact on consumer confidence was far greater than the terrorist attacks of Sept. 11, 2001 and on par with the collapse of Lehman Brothers. And that was when we didn't ultimately default.
For those debating what the impact of not raising the debt ceiling might be, the slide above tells you everything you need to know. If history is any guide, the word "catastrophic" fits.