Apparently Podesta is confident that he is untouchable--he is getting very bold in his Tweets.

Podesta taunted Trump with this Tweet, comparing it to Nixon's Watergate scandal:

http://i.dailymail.co.uk/i/pix/2017/05/09/23/40252A2200000578-4489966-image-m-61_1494368714505.jpg

By comparing the firing of Comey with President Nixon's "Saturday Night Massacre", Podesta is alluding to how the Nixon administration was brought down during the Watergate scandal.

Nixon fired special prosecutor Archibald Cox and there were resignations to follow. Of course, the exaggerated term "Saturday Night Massacre" was an invention of political commentators.

Source: https://en.wikipedia.org/wiki/Saturday_Night_Massacre

Those of an age to recall Nixon and this "massacre" know that this was the final straw in bringing down the Nixon presidency, so Podesta's use of this comparison would indicate his hopes of the firing of Comey having the same effect on the Trump presidency.

Of course firing the FBI head at the urging of the attorney general, and assistant attorney general is nothing the same as firing a special prosecutor. The letters from Trumps advisors are reproduced in this article: http://www.dailymail.co.uk/ushome/index.html

Podesta's Tweet has gone viral with many chiming in. Here are some examples:

http://www.rawstory.com/2017/05/saturday-night-massacre-trumps-firing-of-comey-compared-to-nixon-watergate-firings/

Nixon’s ‘Saturday Night Massacre’ and #TuesdayNightMassacre Blow Up on Twitter After Comey Firing":

Source: http://www.mediaite.com/online/nixons-saturday-night-massacre-and-tuesdaynightmassacre-blow-up-on-twitter-after-comey-firing/