Why is there a debate at all?
Because people want it. Suppose (just hypothetically) you were getting a subsidy from the public, and that the subsidy served no useful purpose. Then suppose someone said, "Hey, this is getting expensive and unless we change the rules for how we compute your subsidy, it's going to get more expensive in the future."
You would call for debate. Why wouldn't you? What've you got to lose?
Futhermore, if you lost that debate, and then people started saying, "Let's change the rules for your subsidy, either eliminating or reducing it," you would call for debate, because since your subsidy serves no useful purpose, the rational course of action is going to be to eliminate your subsidy.
I think we're pretty much now at the stage, where we should start seeing some some great arguments for how pollution reduces crime (and pollution solves some other social problems as well), and that if you want to be tough on crime (and address other social ills), then we need to increase pollution. (That'll be the liberal argument, put forth by Republicans.)
This will be countered by the argument that increasing pollution just makes industries become dependent upon pollution, cleaning up the pollution is needlessly expensive, and industries that pollute could be just as productive without the pollution. (That's the conservative argument, put forth by Democrats.)