The crop of course stuck, as other colonies went on to implement similar measures to increase their chances for survival: hemp fiber could make strong ropes and durable canvas textiles, and they were certainly aware of some nutritional benefit from the modern era's latest superfood: hemp seed. Gradually, the colonies began to separate themselves from British rule as more local producers of hemp discovered the talent and methodology to refine raw materials into more finished products, which the Crown had specific laws against in order to maintain its guise of authority over the Americas.
Even early drafts of both the Declaration of Independence and the Constitution were on hemp paper – lucky for historians hemp paper far outlasts paper from timber. Fast-forward to the 20th century, where hemp served as a critical crop for both world wars in the form of rope, uniforms and parachute cording, most of which was produced in the Midwest.
But with the passage of the Marihuana Tax Act (1937), hemp production in the United States essentially ended...well, with the exception of WWII and the success of the federal government's “Hemp for Victory” propaganda campaign. Soon, the option of cheaper synthetic fabrics, along with other economic factors, drove hemp into the impractical for most of America’s farmers, even though Popular Mechanics magazine once proclaimed hemp would become the "New Billion Dollar Crop."
But it wasn't enough. The racially-motivated drug hysterics of the time and exploitation films like Reefer Madness proved too much in tandem with the day's socio-political forces, and so began the gradual prohibition and forced ignorance of cannabis in America (see below).
Decades later amid a growing anti-war movement and social upheaval in the U.S., Richard Nixon eagerly passed the Controlled Substances Act (1970), thus categorizing any product containing THC as a Schedule I drug and classifying cannabis among the likes of cocaine and heroin, and without medicinal application, although the government's cannabis patent suggests otherwise.
Not only did this move position hemp directly beneath the heavy hand of the DEA – whose funding exploded in the 80s and 90s in an effort to fight the war on drugs (mostly cannabis) – it also became a tool to eliminate political dissent and scientific study. To cultivate cannabis for research, a hopeful grower once had to submit piles of documentation to the DEA and meet many specific and costly security mandates, plus risking your scholarly relationships. It's probably no surprise very few permits have been issued over the decades, hence many of our current cannabis misunderstandings. 
Since the grassroots resurgence in state-based hemp movements following the 2014 Farm Bill and the broad support for legalization, it appears the DEA's grip on cannabis has begun to weaken, even without mention of the latest victories for cannabis legislation.
Because of hemp's legal status in the U.S., modern agricultural techniques of plant breeding and harvesting technology have not had the same opportunity to evolve as crops like corn or soybeans, putting America further behind the hemp growing countries managing to regulate without a hitch. Considering America’s precedence as a world agricultural powerhouse and it's recent commitment to cut carbon and focus on sustainability, it seems more farmers, politicians and consumers could get curious about hemp’s potential to grow America toward greener industry.
HEMP FOR VICTORY! (1942 – US Dept. of Agriculture)
