With that signature, hemp will become legal nationwide. And cannabidiol (CBD) derived from hemp will become, well, a little less illegal. But not precisely legal—yet. It's complicated.

On page 738 of the massive, 807-page, $867 billion spending bill is a provision inserted by Senate Majority Leader Mitch McConnell that legalizes hemp production, processing, and sale—removing the plant from the Controlled Substances Act..

"Making it official with my hemp pen," he tweeted out Monday in advance of Senate approval of the bill. The measure went to the House for final approval two days later, where a final tally of 369 House members approved the bill.

Just Another Commodity Crop

The new law would make hemp a legal agriculture commodity with the US Department of Agriculture retaining federal authority over the crop. (Hemp is legally defined as the plant Cannabis sativa with a THC content of less than 0.3%.)