> You cannot do this if the big Wall Street firms collapse.

I'm not sure what you mean by this. Wall Street firms as such don't have deposits; Wachovia, Washington Mutual, and a number of smaller but still large banks were handled in similar ways to avoid any loss of even uninsured deposits.

Perhaps you're under the impression that the FDIC paid out of its fund for those deposits? (e: Originally I claimed this impression was wrong, but in fact I was wrong.)