And the North Dakota legislature wants them to as well. They've passed 5 bills related to the issue this year, and the governor has signed three of them. The laws basically lay out a framework for growing industrial hemp in North Dakota, despite the fact that it is still illegal at the federal level.
There are at least 7 other states - including California and Minnesota - that are attempting to pass state laws that legalize growing industrial hemp as a commercial crop. Growing marijuana, which has high levels of THC (hemp does not), would still be illegal. The fact is, products with hemp can be sold in the United States, but hemp can't be grown here (without a DEA license, which they don't give out). So all the hemp used in products sold here in the U.S. is imported. Which doesn't make much sense.
Representative Ron Paul (R-TX) introduced a bill on industrial hemp in the U.S. Congress - H.R. 1009 - earlier this year, with a number of Democratic sponsors, including Barney Frank (D-MA). Paul is running for president. He introduced similar legislation in 2005 that went nowhere. The same thing will probably happen with this bill, but similar bills will continue to be introduced in the coming years. So someday, we may see a class of industrial hemp defined at the federal level, and let individual states decide whether to allow hemp farming or not.