While I agree with you that more than 2 parties is not viable in this country without structural changes to our electoral system, I am undecided about whether it would be desirable here. The problem with more than 2 parties is that it opens the door for extremist parties to get in by plurality vote, while the majority of sane voters split among several more moderate parties. I think we have been largely successful in this country because we have had a degree of stability in our politics and government over the generations. We tend to change gradually rather than implement major, radical changes over night.
In a proportional system like in Israel for example, we can see that the counter-productive settlement policies are continued because the major parties in power had to make deals with the smaller religious parties to form a coalition.
If an extremist agenda wins the day because it is broadly popular, I do not mind. However, I'm not comfortable with extremists gaining traction through the backdoor, because of the vagaries of proportional representation, or plurality wins all systems.
I wouldn't mind a viable centrist third party here in the US, which presumably would draw away moderates from both the current parties, and would provide voters with a third choice. However, any structural change that would make such a thing possible would open to the door for radical and destabilizing elements.
- wolf