Matt Bailey puts it specifically, Niven and Pournelle put it generally, but the message is the same. There are a lot of good ideas out there, but they're not good at all times and all places. In fact, sometimes, if implemented, they're bad ideas.
Here's an idea. A country should have democratic elections, and all political parties should be allowed to participate. A good idea? In the US in 2016? Sure. In. say, Denmark in 2010? No problem. Even maybe in Japan in 1997? Sounds good! In 1978 in Zimbabwe? Not so much.
But Jimmy Carter thought so. He insisted that Mugabe's communist party be included in the election. So, reacting to American pressure, they had another election, Mugabe was elected, and the country has been a miserable hell-hole ever since. Google Jimmy Carter, Mugabe, and learn all about it.
By the same principle, this is not the time to elect a doctrinaire Libertarian to the Presidency. As Matt says, we're past the point where libertarian reforms would have worked. At this point, they can only make things worse. It's Trump time, folks. So, unless you want the country to fall apart, any other vote would be idiotic.
But if you're so committed to the idea of voting for a libertarian that you feel you just have to. Ponder this, and look at the link:
Hillary Clinton has threatened to trash the Second Amendment, but so far, only Gary Johnson has gone so far as to literally throw firearms in the trash. [link]
Quibcag: What with all the talk of vaccines and tourniquets, I picked Rika Shiguma as the illustration. Actually, she's not a doctor, but she sure looks like one in her cute little lab coat.