I'd like to offer some ideas on how to include third-party and independent candidates in the 1.2 or later version of the game.
Obviously such candidates need extra obstacles to overcome, but for game purposes they should have a legitimate, if longshot, chance to win.
They could start with fewer points to allocate than Democratic and Republican candidates, perhaps two-thirds as many. A third-party or independent candidate also could be blocked from spending any points in certain categories, such as:
* Fund raising. Sure, a Perot-type character could spend a lot of his own money, but minor-party candidates draw much less in donations.
* Philosophy. As I asked about in another thread, I'm unsure what spending points here constitutes to a Democrat or Republican, but perhaps this category could be used to simulate that even the Greens and Libertarians still have tiny bases comparatively.
* Comeliness. Yes, 0 points here would seem silly if a player used Jennifer Granholm or Arnold Schwarzenegger as an independent (which, of course, couldn't happen anyway because neither was born in the United States), but it would simulate the difficulty of gaining much popular support early in the race.
* Opposition. Though the 2 main parties have major differences, they share an interest in keeping other rivals out.
The other obstacle for these candidates would involve media. Local reporters might decline to interview them X percent of the time, and naturally they'd have a lower base probability of getting national media opportunities.
I think I see 1 less-obvious reason why having a 3rd candidate would be difficult in this game. From what I've read on this site, a lot of the data involves measuring what Democrats and Republicans separately think on a given issue, thus allowing appropriate responses from party members when a candidate takes a stand.
I doubt there's much polling data on what the nation's minor-party rank-and-file members think about a given issue, though for the few minor parties with full-fledged ideologies (such as the Greens and Libertarians) one probably could take a good guess. And true independent candidates wouldn't even have that small base to play to in the game.