Here is my view on NA, YMMV.
New America is a product of that unfortunate heyday of 80s racial groups that occurred in the NW. Guys like these fellas:
http://en.wikipedia.org/wiki/Aryan_Nations
http://en.wikipedia.org/wiki/The_Order_(group)
Throw in some concern about televangelism and other issues, and voila, here comes New America as a fictional construct.
Now, here's my POV. Are there racist types in the ranks? Um, yup. Anybody with any connection to the military has known at least one. They're always the scum we'd like to introduce to a towel party, but most of the time, the bastards are careful enough to keep their mouths shut. When they do screw up though, it's pretty spectacular. The good news is, they're usually the leader of a bunch of "gun-store commando" types I would not trust with a frosting gun, let alone a real one.
Hughes was basically an allegory for David Duke, make him more media savvy and with a bigger bankroll, and is New America possible? Yup. Fill out the right forms and suddenly, you've got 501(c)(3) status. Get a good media arm and you can convince the press you love puppies and kittens and all this "racist" talk is just that, talk. (Trust me, in my current position, I've dealt with the press...most of the domestic press are more content with being talking heads than getting the truth).
I agree with Web on folks "getting with the program". After something like Twilight, people are going to want people to blame for their circumstances. "Hey that <fill in the blank> has more than me!" If New America leads the mob that loots said guy's home and business, assuming he has the latter, and re-distributes it to folks who have none? Well, they just bought themselves allies, and if those grasshoppers happen to have a certain skin color exclusively? That's just a coincidence, friends.
And if you do happen to be a white redneck stereotype who manages to test into being a Second and is put over your better educated minority or just simply more liberal neighbors when they're made Thirds? Well, power is a hell of an aphrodisiac...and you just got that guy's loyalty for life. He'll do anything for you, even if it's pretty distasteful. Look at the biographies of most of the SS's top people. Before Himmler tapped them on the shoulder? They were rather unsuccessful people.
Then, add in people who don't trust the government for whatever reason, NA yanks their paranoia chain (and hey, as Olefin put it, the Feds have brought on the nuclear war, damn the facts that the Soviets had something to do with it too). A few choice ideas their way, and NA's propaganda section has got them eating out of their hand.
Simply put, is NA possible as written? It needs some work, perhaps not as strong as written, but I always pictured New America as being more willing to win by subterfuge, propaganda and just plain underhanded behavior, seeing force as something they use only when they've suborned the other local authorities.