It depends on which goal they are more interested in.
If the goal is exclusively tax revenue, sin taxes are great. But there are ways to mitigate the effect on lower and middle income people if that is also a priority.
Cap-and-trade, had it gone further than it did, would have provided an interesting test for Obama's priorities. Had it not been DOA and proceeded further, it was my expectation that tax credits would have been provided to address the problem of lower and middle income people to mitigate the effect. (For example, in most jurisdictions, there are already like programs in place to provide low cost or subsidized heating) The desired effect would be to shove the bulk of the cost of cap-and-trade to upper-middle and higher income consumers, which politically, is what the Democrats really want.
The downsides of this approach is that it makes an already convoluted and distorted tax code even more so, would have had other "unintended consequences" and it only works well for "sins" that everyone commits; There's no practical way to apply it to smokers.
