S&P's April 18, 2011 warning shot was the beginning of one of the most dramatic episodes in US fiscal history. The 'negative outlook' was unprecedented for American sovereign debt and sent a clear message to Congress: resolve the debt ceiling or face a downgrade. Congress did pass the Budget Control Act on August 2 — but S&P downgraded anyway on August 5, triggering 'Black Monday' on August 8 when the Dow fell over 600 points.