According to Wikipedia, after graduating from University of Edinburgh Medical School in 1829, O'Shaughnessy joined the British East India Company and moved to Calcutta where he studied botanical pharmacology, galvanic electricity and underwater conduction. He validated folk use of cannabis in India, discovered new applications and ultimately recommended cannabis for a great variety of therapeutic purposes. A man of many talents, during the years 1853-5, he installed 3500 miles of telegraph across India and wrote numerous manuals and reports on his telegraph inventions. In 1856 O'Shaughnessy was knighted by Queen Victoria for his work on the telegraph.
Modern experience has amply verified and expanded on O'Shaughnessy's pioneer work demonstrating the medical efficacy of cannabis and its relative safety compared to synthetic drugs. However, in blatant contradiction to scientific fact, the US government insists on classifying marijuana as a Schedule 1 substance "having no currently acceptable medical use".
The American War in Iraq is based on a lie: that Saddam Hussein possessed WMDs.
The American War on Drugs is also based on a lie: that marijuana is useless as a medicine.
If an order to fight or a law of the land is based on a lie, is a citizen still bound to obey it? And what sort of country would compel its citizens to obey laws based on lies?