[steve-b]

effective suppression of marijuana cultivation and sale in interstate commerce necessarily requires its suppression in intrastate commerce

Even if that were true, it is simply not relevant. To illustrate by analogy: If I'm hired to secure an office building against vandalism and graffiti, I can argue that I can't effectively do it unless I'm allowed to go into the surrounding community and suppress criminality in the area generally -- but that's just too bad, because my authority is still limited to the property of the guy who hired me.

[robertpaulsen]

"but that's just too bad, because my authority is still limited to the property of the guy who hired me"

No. He told you that IF the criminality in the area had a substantial effect on your ability to secure the office building against vandalism and graffiti, that you had the power to use necessary and proper force to suppress that criminality.

[Rockingham]

Actually, it is valid because restrictions on and grants of power to government are meant to be construed so as to accomplish their purposes. Thus the First Amendment applies to protect freedom of speech through electronic media even though they were unknown to the era in which the Bill of Rights was adopted.

Your analogy of the building guard breaks down because his grant of authority cannot exceed that of the building owner, who presumably does not own the surrounding homes. Of course, a cop hired as a building guard might have additional powers of enforcement that allowed him to chase down vandals and graffiti artists in hot pursuit.

As for the commerce clause, the suppression of marijuana requires a comprehensive effort because the stuff can cultivated in commercial quantities in a small space. If a pot plant or two under a grow light in a garage seems harmless and beyond the reach of the federal commerce power, consider the effect of the same putative intrastate exclusion applied to the cultivation of some noxious species like piranha or Asian snakehead fish or anthrax cultivation.

Notably, this line of reasoning treats marijuana as one of a special class of cases in which the federal commerce clause necessarily extends further than it would in most instances. This ought to be of some comfort to those who are not marijuana advocates and who otherwise prefer a limited scope for the federal commerce clause. Am I wrong in thinking that there are only a few here whose want the commerce clause limited but who are not also marijuana advocates?