Libertarianism is a form of conservatism, some would argue a purer form than social conservatism which is often more theological than politically conservative. One cannot be a libertarian AND  SOCIAL conservative, both - unless one is one of those very rare social conservatives whose own personal morality would be deemed socially conservative (drug use bad, homosexuality bad, unusual consensual sex practices bad, missionary position with spouse good, evangelical  church attendance good, etc.) - but who also think it's wrong to dictate to others via criminal and other official sanctions what their OWN personal morality should be.  Sadly, most social conservatives aren't libertarians but are dictatorial busy bodies who insist on running other people's lives for them by threatening them with jail if they don't follow their own rigid interpretation of
what's moral behaviour & what's not.