Well, sure there’s a rational argument for smoking – it’s the same argument for drinking tequila shooters, or lighting up a doobie, or eating candy, or going skydiving: people enjoy doing it, in spite of the health risks involved.
Sure, we could ban it, just like we banned alcohol via Prohibition or like we ban marijuana today. And we can see how well those measures have worked out.
But let’s draw an important distinction that has gotten muddled in this thread: the difference between what government should be able to do and what private enterprises should be able to do. The ability of the latter to impose restrictions on their employees is broader than the former.
A private employer can deny you employment for pretty much any reason, outside of certain prohibited reasons defined by civil rights laws (race, gender, etc). Which is as it should be. It has been shown that smokers, as a class, lose more productive time than their nonsmoking counterparts, due both to break times and medical leave time taken. That is a legitimate concern for an employer, as are the increased costs to the company’s health-care program, if any such program is offered.
Consider salaried white-collar employees, for whom “breaks” are a fairly fluid concept. Also note that, contra to what some have written earlier in this thread, medical leave is not the equivelant of vacation time, to be taken at a whim; an employer can reasonably expect his employees to take modest steps to minimize their likelihood of needing sick days off.
Sure, many individual smokers are careful, diligent workers who are relatively healthy in spite of their habit. But weeding out the diligent from the unproductive imposes costs of its own; an employer may well find it more cost-effective to essentially play the odds. Particularly for large organizations, making decisions based on carefully tailored evaulations of each individual may not be practical.
But there’s a countervailing interest favoring smokers: a company that refuses to hire or retain smokers is intentionally reducing their available supply of labor. That raises their cost of hiring – it means they will have to interview more candidates, and may need to pay those candidates more money. It also means that they may be passing on talented, creative people who will provide a competitive edge to their competitors.
There are also attendant costs to employee morale – even nonsmokers will probably dislike the notion of their employer dictating their private vices, and may be concerned that their vices will be targeted next (“When they came for the smokers, I said nothing because I was not a smoker; when they came for the doughnut-eaters, I said nothing because I did not eat doughnuts…”). That morale cost will hurt productivity, and may make it more difficult for the company to attract talented people. Again, hiring costs will rise because potential employees will want to be compensated for giving up the right to engage in perfectly legal activities.
In short, the market will sort this out.