"special interest"
There is no ATLA political party, no NEA political party, no Pharma political party, no insurance polticial party, no NRA political party, no AARP political party, no US chamber of commerce political party, no tobacco political party, no NARAL poltical party etc. etc. These alphabet organizations are not parties, they exist to funnel campaign contributions (i.e. "buy") "demopublican" people whom they like, not to get THEIR OWN MEMBERS to office.
"There is no ATLA political party, no NEA political party, no Pharma political party, no insurance polticial party, no NRA political party, no AARP political party, no US chamber of commerce political party, no tobacco political party, no NARAL poltical party etc. etc. These alphabet organizations are not parties, they exist to funnel campaign contributions (i.e. "buy") "demopublican" people whom they like, not to get THEIR OWN MEMBERS to office"
Only because most of them aren't big enough to do so in a two-party system. The large ones (such as the environmental special interests) already have their own parties. Some of the very parties that you listed as potentially forming are special interests, albeit the larger ones. Most of the people on this forum would have few qualms about voting for a gun-rights party.
The special interests that aren't big enough to form their own parties will just be able, with more parties to choose from, find a party that represents their interests well enough to just get more bang for their buck. A real Libertarian party would be a perfect fit for the tobacco industry in trying keep the government from passing laws against smoking.
Oh, wait, I forgot, in your system third parties will fund their campaigns with sunshine and pixie dust.