I feel compelled to note that while historically Libertarians have been more likely to vote for Republicans as second preference, I don't think that's true any more with the veer the Republican party has taken in the past 4 years of the administration.
That's an interesting perspective. I think it's still a bit of both. Yes, GOP has been shifting away from small-government, balanced budgets, and free trade, leaving the Libertarian platform to pick up those staunch proponents. However, the socially liberal aspects of the Libertarian party, like drug decriminalization, criminal justice reform, and gay marriage have been cornerstones of Libertarianism and Republicans would still be crossing over on those issues that haven't been a part of the historical Republican base.
Another interesting difference is that the current Libertarian nominee's environmental platform is based on Nuclear, solar, and other renewables[0], in contrast to Republicans' usual Oil and Gas position.
