I should mention that there are also disagreements with libertarians on foreign policy. They want to curtail the defense and have come to think of the military as a force that has caused more harm than good. They don’t value a war on terror or understand its ramifications. They do not get the Islamic threats. There is one group that is even against Israeli and any Jewish state. There is another that is very anti-war and wants to end all wars.
They think everything is a civil liberties issue or causing a police state and while some of it is understandable and true, they oppose measures of any kind to track or punish the enemy. They are heavily opposed to the military.
They support cutting defense. Now I don’t mind cutting some of the defense if not needed and fixing departments as long as it does not jeopardize security. But some libertarians want it cut as drastic as Obama or even more because war is bad to them and they see it as us being the oppressors around the world. Hence they call republican, conservatives or folks who support the military and defense as neo-cons.
They [libertarians] actually have a point here: it is destructive to our own sovereignty to impose our will upon other nations via the military (i.e. being "world police") -- this is because in doing so we assert that might makes right, and therefore have absolutely no legal or moral defense (w/o becoming hypocrites) if and when that should be done to us (think UN enforcement of small-arms treaty/agreement).
Not that our government isn't hypocritical in the extreme now: they have cited state sponsored terrorism as justification for forcing [regime] changes to foreign states -- and then executed Operation Fast & Furious, which is state sponsored terrorism.
They don’t value a war on terror or understand its ramifications.
I'm a veteran and I'm against a "War on Terror." Why? Because there is no victory condition -- certainly not one that is militarily attainable. Like the War on Drugs or the War on Poverty, the 'target' of the declared 'war' is ever malleable and will always be changed to further government control; if the War on Drugs was ever close to eradicating drugs on the street the 'goal' would be changed to include prescription drug abuse -- likewise, if the War on Terror were close to being won there would be one thing sure to change: the definition of terrorist, allowing for more government control/action {actually, this has already happened in some degree with militia, returning vets, third-party supporters, and anti-abortionists all being flagged as possible terrorist groups}.
In short, I'm against any 'war'/policy that doesn't have well-defined and attainable/enforceable goals.