I never thought the economy properly recovered from the 2008 crash but what will be popularly called a "double dip" and officially classified as technically another recession, (too far past the earlier official recession's end to count as related to it although it really is), will be seen as starting about now with the debt-ceiling crisis a designated "tipping point". Although it was going to happen anyhow it might have waited until as late as next year. I previously guessed that it would be seen as starting with a weak Christmas buying season this year -- but the dating of it is largely arbitrary and ultimately of no great importance except as it might play into eventual political talking points.
The inevitability of it has to do with far too little being done to help deeply indebted households and to create work for the unemployed and with the lack of serious structural reforms addressing what led to the 2008 bubble burst in the first place.
The stock market has been in a purposely engineered by the Fed bubble to replace the burst real estate bubble. The unrealistic hope is that the "wealth effect" among the wealthy will somehow spur economic recovery despite the continued misery of ordinary household savers, (because of low interest rates), and debtors, (because of high indebtedness). The debt ceiling crisis could be the pin to puncture the equities bubble because traders with enormous leveraged positions are threatened by a downgrade of "risk free" Treasuries used as collateral. They will react by de-leveraging, selling stocks and buying more Treasuries to use as extra collateral as an offset to the downgrade risk.