The Republicans argue against "regulations." They want to do away with all of them, and if you talk to serious Republican, they really think they mean it.
They have no idea what doing away with environmental regulations would mean for their children and grandchildren and many future generations of not just children but life of all kinds.
For me Obama's biggest appeal is that, in spite of the free reign given to Monsanto and his failure to definitively say absolutely not to the Keystone pipeline, he has maintained some regulation of the environment -- at least some. The Republicans would not do that.