Tough stuff lady! You work at the pleasure of the employer, not the other way around. The employer told you "SEE YA, WOULDN'T WANNA BE YA!"
And how exactly would you react to being fired for being a Republican?
She accepted employment, thereby terminating her search for employment with another company. They did not tell her that not smoking was a condition of employment. They could just have easily asked her if she wore a thong and fired her for that. The question should have been asked prior to the offer of employment, and prior to her acceptance of such. This is not an acceptable business practice. Had they asked her during the interview, then told her that they had nothing for her because she was a smoker, I wouldn't have a problem with that. She did nothing wrong.
Well, at the least, they owe her compensation for the amount of time of hers they wasted in the interview\prep process.