There is this 'old American politician with nothing to loose' phenomenon which I have personally observed in the cases of Paul Nitze or Admiral Elmo Zumvalt: when they are old have have nothing to loose, when they are beyond reach of the US Nomenklatura, they begin saying out loud what everybody in US politics knows, but dares not say.
This time it is Mike Gravel who simply decided to speak the plain truth. It was a delight to hear him. See for yourself: