I really hate this answer. The parties are not part of the government, yet run the government. They have set it up where they are the only 2 parties that are viable. You shouldn't punish someone's rights just because they are independent. This is coming from a registered Democrat.
The partys have done no such thing. The founders and the system we have lend to a majority / minority dualistic system of government and that's what causes the formation of two camps.
There's also nothing stopping a left leaning coalition from working within the system and making the case to lead the party in one direction over another. Obama did it to beat Clinton. History is ripe with example of how that leads to change within the two party system.
The issue isn't the partys or the system.
The issue is a tiny, loud minority isn't getting its way fast enough, can't figure out how to form a broad coalition; so they're kicking and screaming and undermining their own efforts.
And soon they'll go back shutting down highways and sitting in squares and complaining that the system doesn't work; when instead of working to bring over hearts and minds they just gave up after 6 months of keyboard bashing and being dicks.