Nixon's War on Weed becomes a research project
When Richard Nixon declared a war on drugs in the 1970's the midwest was already awash in hemp. Spread by birds, the remnants of the 1940's Hemp for Victory grew in the ditches. The DEA domestic cannabis eradication program has destroyed this ditchweed every year since they first received funding. Now state like Nebraska will once again be growing hemp legally.
Nebraska is coming on board as the most recent state to take advantage of the US Farm Act. The US Farm Act allows Universities to study hemp if it is approved by state law. Here is an article about the Nebraska research program.