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Libertarian party is moderate.
A survey by David Kirby and David Boaz found a minimum of 14 percent American voters to have libertarian-leaning views.
It's fiscally conservative. It doesn't run others' people business.
It's most compatible with free market and capitalism which most people are used to.
Yet, it didn't get much seats.
In presidential election, that would be understandable. You need to win and only the big 2 parties can win. But in parliament election?
We don't have 1% libertarians in most US states (source).