Those are not key issues for libertarians. I am a libertarian, and voted a straight Republican ticket this year, but I have voted for Libertarians before and will do it again.
I want closed borders, State's choice on abortion (I'm pro-life) and freedom for people do what they like in their houses and in private if it doesn't harm another person. People should be able to smoke pot if they want. Go ahead and drink until you can't feel your face, then drive home from a party or a bar, but don't smoke a joint in your living room on a Friday night. It's just a stupid law. I don't like gay marriage, my solution would be to remove any government regulation on marriage. If you can get a church to marry you, good, great, fine whatever. If you can get an insurance company to recognize partner benifits, great, fine whatever. There are a lot of things that we could fix in our world by getting the government the hell out of.
As far as troops overseas... except for actual real live "declared" wars, or situations of Letters of Marquee and Reprisal, why would we need more than a few key bases across the globe? Why does Japan need a Marines base? Why does Germany need an Army base? Bottom line is we were totally justified, both morally and Constitutionally, to take action in Afghanistan. But the situation in Iraq is a mess both Constitutionally, fiscally, in terms of loss of life, our standing on the world stage, and its effects on our elections as we just saw.
If Republicans were following the Constitution in letter and spirit, and not just Dem-lite, we wouldn't have a need for a Libertarian party, and libertarians could exist within the GOP. Instead, the GOP is more interested in the short-sighted goal of winning elections as opposed to the hearts and minds of people in favor of a Republican, Constitutionally responsible form of government, and in the future we're all going to suffer.
"or situations of Letters of Marquee and Reprisal"
Oh, my sides!
"People should be able to smoke pot if they want."
That's really all you needed to post. The rest is window-dressing.
I'm also a libertarian and with the exception of a few local races where I voted for a Democratic candidate, I voted mostly Conservative, entirely for national and state races. I'm in agreement with what you posted.