US Debt agreement failure - consequences in a nutshell

So, a default on the World's largest economy and debtor?

I think we would see a credit rating degradation of US bonds and therefore consequences on credit cost would that would rise in the US (and on other regions in the world that are exposed to US sovereign debt), making it more expensive to get credit. But this would also affect current credits, as most of their spreads are set vs floating indexes. This could then prompt a new wave of defaults by individuals as well as businesses, creating a possible recession.

This is the simple scenario - and we all hope not to understand if it would be like this.

http://economia.publico.pt/Noticia/obama-alerta-para-o-risco-de-uma-crise-economica-provocada-por-washington_1504715