What is a Republican?

I'm a republican but I am totally lost in my party's choices in candidates and beliefs. I feel like all I have to do tell a joke is say "I'm a republican" and that's the punchline. I'm not an evangelical Christian, I'm not religious even to the slightest degree. I don't care what gay people do or want to do as long as it's in private and doesn't involve me. Obamacare? Don't care don't care, I hate the insurance industry and would greatly enjoy watching it squirm for once. I believe in evolution, global warming has occurred before it's not new and I believe in legalizing medical marijuana. Ron Paul seems to make sense to me but everyone says he's whacko. I believe in fiscal responsibility and business opportunity for everyone. I live science and privately funded research and development. I dislike taxes, bailouts and liberal whining, but every time I speak to another republican nowadays, I get accused of being liberal!