Straw Man - our health care system would not be any further burdened by a legalization of a substance already in use by the exact same people who would use if it were legal. Nothing changes, except a war against the citizens of the United States, and also the freeing of police to go after real criminals. You have nothing to worry about from the college student, hippie, and cancer patient.
Legalization in Canada would shift the health care burder from here to there.