Did Senator Obama even once try to stop the "Health Care " or "Economic " Crisis?

Did he propose any legislation or chair or sit on any investigative committees in regards to either "crisis". I find no evidence of any of his actions as a US Senator that even suggest that he did . ---------Ohhh yes i must admit he did dash off a "hurried letter" to voice his "concerns" about the impending economic meltdown a mere 30days before it finally happened . Was Senator Obama really concerned or was he just covering his rear end for politically expediency ?