The only way a 3rd party can become viable is for "grass roots" support. This is what the Tea Party started out as. Now if you guys who want to vote Libertarian or Constitution, that is fine. However, how about starting with sheriffs, county commissioners, city councels, mayors, state representatives and state senators, then work up to state wide elections of senators, US representatives, governors. Once the viability is established, a 3rd party can and will work. Lincoln was the first Republican. He ran against two Democrats (one southern, one northern), and a Whig. The Electoral college had to vote 3-4 times before they picked Lincoln for him to have majority. If I remember the Wigg dropped out first and gave his support to Lincoln, then the northern Democrat who backed Lincoln. The then new Republican party absorbed the old Wiggs and grew.
Problem with Libertarians is most conservatives do not want drugs legalized. They fear them and the consequences. However, I think marijuana should be legal, taxed, and only purchased at state stores or package stores like alcohol, and limit it to 21 or over. Over 500,000 people are in jail because of marijuana, not the other drugs. Yes it might lead to harder drugs, but it already does. A lot of Republicans are coming around on this issue.
Romney might be 60% on my scale, like I said, but this is far better than what we have. At least he is not Far, Far left.