The passing of senior associate justice Antonin Scalia makes this a fitting occasion to marvel at his wit and wisdom.  Note that his technique was to teach his fellow jurists, even taking them on hunting trips.  With the recent unprecedented stay issued by the Supreme Court preventing the EPA from implementing its Clean Power Plan, Scalia's insights in his dissent to the majority decision in Massachusetts v. EPA is particularly useful as a teaching moment.

Even before reaching its discussion of the word "judgment," the Court makes another significant error when it concludes that "§202(a)(1) of the Clean Air Act authorizes EPA to regulate greenhouse gas emissions from new motor vehicles in the event that it forms a 'judgment' that such emissions contribute to climate change." Ante, at 25 (emphasis added). For such authorization, the Court relies on what it calls "the Clean Air Act's capacious definition of 'air pollutant.' " Ante, at 30.

"Air pollutant" is defined by the Act as "any air pollution agent or combination of such agents, including any physical, chemical, … substance or matter which is emitted into or otherwise enters the ambient air." 42 U. S. C. §7602(g). The Court is correct that "[c]arbon dioxide, methane, nitrous oxide, and hydrofluorocarbons," ante, at 26, fit within the second half of that definition: They are "physical, chemical, … substance[s] or matter which [are] emitted into or otherwise ente[r] the ambient air." But the Court mistakenly believes this to be the end of the analysis. In order to be an "air pollutant" under the Act's definition, the "substance or matter [being] emitted into … the ambient air" must also meet the first half of the definition – namely, it must be an "air pollution agent or combination of such agents." The Court simply pretends this half of the definition does not exist.

The Court's analysis faithfully follows the argument advanced by petitioners, which focuses on the word "including" in the statutory definition of "air pollutant." See Brief for Petitioners 13–14. As that argument goes, anything that follows the word "including" must necessarily be a subset of whatever precedes it. Thus, if greenhouse gases qualify under the phrase following the word "including," they must qualify under the phrase preceding it. Since greenhouse gases come within the capacious phrase "any physical, chemical, … substance or matter which is emitted into or otherwise enters the ambient air," they must also be "air pollution agent[s] or combination[s] of such agents," and therefore meet the definition of "air pollutant[s]."

To put this concept within the ken of all the justices on the Supreme Court, we can put it in terms they ought to understand.   All justices of the Supreme Court are federal judges, but not all federal judges are justices of the Supreme Court.  In technical terms, carbon dioxide is emitted into the atmosphere from tailpipes along with air pollutants, but it is not an air pollutant.

Now, it is possible that Supreme Court justices may not have learned Boolean algebra in school.  Perhaps they are so aged that they predate the "New Math," or they are females who suffered the discrimination that held that girls are not capable of learning math because, as Barbie so eloquently put it, "math is hard!"  We know that even Lois Lerner of the IRS has proclaimed that she is not good at math: "I'm a lawyer, not an accountant."  It is our public duty to take up Justice Scalia's cause and educate his peers in SCOTUS about Boolean algebra in the judicial proceedings.

The primary "substance or matter" emitted from an automobile tailpipe is nitrogen gas (Atomic Number 7).  This is because the auto takes in air for the purposes of combustion, and dry air is 75.5267 % nitrogen according to the National Institutes for Standards and Technology (NIST).  Except for a very small fraction that gets oxidized into nitrogen oxides (NOx) at the high combustion temperatures, the nitrogen passes inertly though the engine's cylinders and exits via the tailpipe.

Atmospheric nitrogen is not a pollutant.  Similarly, contrary to Justice John Paul Stevens's majority opinion, water vapor is the "primary species of greenhouse gas."  Water vapor is not a pollutant, either.  The humidity in the intake air, plus the water vapor created as a result of the combustion of the fuel, exits from the tailpipe.  Are the justices attempting to assert that water  vapor is a pollutant?

Let us reconsider Justice Stevens's assertion that carbon dioxide is "the most important species of  agreenhouse gas."

A well-documented rise in global temperatures has coincided with a significant increase in the concentration of carbon dioxide in the atmosphere. Respected scientists believe the two trends are related. For when carbon dioxide is released into the atmosphere, it acts like the ceiling of a greenhouse, trapping solar energy and retarding the escape of reflected heat. It is therefore a species – the most important species – of a "greenhouse gas."

Michael Gillenwater of the Greenhouse Gas Management Institute has this to say on its website (emphasis added):

Water Vapor (H2O). Overall, the most abundant and dominant greenhouse gas in the atmosphere is water vapor. Water vapor is neither long-lived nor well mixed in the atmosphere, varying spatially from 0 to 2 percent (IPCC 1996). In addition, atmospheric water can exist in several physical states including gaseous, liquid, and solid. Human activities are not believed to affect directly the average global concentration of water vapor, but the radiative forcing produced by the increased concentrations of other greenhouse gases may indirectly affect the hydrologic cycle. A warmer atmosphere has an increased water vapor holding capacity, and increased concentrations of water vapor can affect the formation and lifetime of clouds, which can both absorb and reflect solar and terrestrial radiation. Aircraft contrails, which consist of water vapor and other aircraft emittants, are aviation-induced clouds with the same radiative forcing effects as high-altitude cirrus clouds (IPCC 1999).

Perhaps another example of Boolean algebra might help the justices.  Water vapor is "the most abundant and dominant greenhouse gas," but it is not a pollutant.  Justice Stevens built his opinion on a false premise.