Proxmire was concerned about the nation's rising debt level. The bill he wanted to stall action on authorizing a total debt of $1 trillion. link
Wasn’t it Proxmire, WI, who gave out the “Golden Fleece” awards for the biggest boondoggles?
Actually the longest fiflibuster was by Sen. Strom Thurmond in 1957 —a little over 24 hours.