Libertarianism = Anarchy?

Libertarians often say they aren't anarchists, they just believe in really small government.  However in order to join the Libertarian Party you must certify that you are against the initiation of force.  Anarchy is described as the lack of a hierarchal authority, no one has any power over anyone else (ideally).  Taken to its logical conclusion, a libertarian government obviously could not do anything without absolute consent of each and every individual.  It could not even levy any taxes, because taxes by their very definition are an initiation of force.  If people give willingly it's called donations.  Government itself is all about force and control.  It makes people do things that might not be good for them, but good for the group as a whole which libertarians find abhorrent.  How can a party that requires such a pledge morally participate in governmental elections unless their only platform was to immediately dissolve the government once elected?  Which ironically would require a significant power grab for them to even do so.  Why can't libertarians just fess up and admit they're anarchists?

Libertarianism isn't anarchy.  Libertarians don't believe in no-government, they believe in 'less' government.  It would be far more accurate to simply say they favor less government.  This does not mean no government, it does not mean no laws, no military, etc.  Libertarians support the military, the courts, the police force, and other more or less essential parts of the government.  They just want to get rid of a lot of arguably unnecessary parts of government, such as welfare for example. 

Libertarians think, generally, that unless an activity you are doing causes direct harm to another individual, you should be free to do it (such as owning a gun, looking at porn, or smoking pot, which, believe it or not, some people would like to restrict or make outright illegal...)  To a libertarian, government should be there to safeguard freedom, and it should only exist to the extent necessary to safeguard the rest of your freedoms from violation by others (such as foreign governments, or criminals.)  Thus, they advocate a police force, military, etc.