Absolutely embarrassing mob reaction to nothing is what this is, and it couldn't be more unproductive given the tendency for Those Who Are Right Once In A Blue Moon to glom on to any point they've been in the right about, and never let the other side live it down.
Furthermore, to suggest that he was trying to neologize, with something as sophisticated as "Governmentnik", is as outlandishly speculative as thinking that this tame, vanilla person would "slip" and say the N-word in a campaign appearance. And by "tame, vanilla", I don't mean he's not a middling everymans' fascist, but he's certainly not the type of uncouth loose-lipped racist that can be found in the comments section of the Fox News blog, or ranting in the periphery of the tea party meetups.
So this is my take folks; I only decided to diary it because no one else has mentioned what seemed, to me, immediately obvious.
He was on track to say "Big Government", dyslexically said Government first, and before his lingual system could catch up(ie move on to the next ostensible point), his slow brain tried to go back and put in the missed word, "Big". However, since "Big" was then in the slot that "Government" should've taken, his vocalization utilized the prevalent consonant from Government; "N", in the place of "B". All of this takes place in a split second of course...
Thing is, when your entire expressive speech revolves around repeating the same catch phrases over and over, these things are bound to happen. I mean it's not like righties have original speech about Serious Things, ever. Haven't we learned that, yet?