I am not of the opinion that petitions work, especially when directed at people who are paid to ignore you since they work for the opposition - this applies to certain government agencies, and the alphabet soup organisations.
Instead, we need to get the media on our side; try to get the correct information to people in positions of power and influence; try to make this a voting issue; donate money to CASAA to help their campaigning and practical work; write letters (physical letters that is) to your Representative; and convert as many smokers as possible to better alternatives. In particular we need more numbers and a much bigger media presence.
If petitions are easy to sign, then why not - but ultimately other things will produce better results. I'm sorry to say this but at ECF we are about done with petitions, because they are sometimes badly targeted and take too many resources to complete (and this mainly refers to an individual's willingness to work for a better situation). People have a limited amount of energy to expend on these things, and it is better to expend that energy in the most efficient way. Given one choice alone, I'd recommend donating to CASAA, because they get provable results.