It was the act which kept gambling separate from banking, or rather "investments separate from depository banking", and it was the repeal of the rule which allowed the financial markets to go bonkers. We are now experiencing the results of that.
Now a
few lonely voices in the wilderness are mentioning that perhaps we should bring the Glass-Steagall Act back. Watch how well that flies. Have your popcorn ready, too, because most of the powerful don't want it back.