You mean the way they haven't been able to manipulate the two-party system? ![grin =D](http://www.armedpolitesociety.com/Smileys/default/grin.gif)
What exactly is sacrosanct about two--and no more--parties? Please illuminate.
Machiavelli explained it pretty well in
Discourses on Livy, IIRC. It may have been
The Prince~~or maybe he just touched on the topic there. The more "parties" there are, the weaker they are (relatively) --or tend to be -- and the more contentious they become, thus making it
easier for a aggressive, ruthless individual to take over and become a tyrant. That wasn't the end of it so don't lose faith yet; eventually the tyrant would be overthrown/assassinated, whatever, and another cycle would begin with a multiple party, or multiple leader type system. The result is political instability.
There's really nothing "sacrosanct" about a two party system, except ours atleast has been fairly stable with no coups d'tates. Some people think we had a "fling" with a 3 party system way back in the mid 19th century when the republican party evolved but the reality is the Whig party was pretty much all but condemned to the history books when the republican party ascended.
BTW there is no real reason why Machiavelli would claim we could not have a tyrant in our system, he just believed in an unstable system with weaker members it was more likely to happen.