Personal liberty is both enshrined in the US Constitution and liberally permeates American political discourse. Put another way, having the “freedom to” (have free speech, bear arms, etc) is a big deal. Consequently, it is then something of a real head-scratcher as to why the full, federal legalization of cannabis in the US remains such a sticking point. You have the right to purchase a high-powered AR-15 weapon of war, with all of the risks that that entails, yet the right to use cannabis still languishes under a huge question mark.
Currently, federal law prohibits the use of cannabis for any use, be that medical or recreational. However, at present, ten states, plus Washington DC, allow adults over the age of 21 to use marijuana on a recreational basis, while 33 states allow for the use of medical marijuana.  So, while that’s progress of a kind, that still means that there are plenty of states where recreational use, and even medical use, can lead to the user ending up in significant legal jeopardy. The case for complete federal legalization is though a compelling one.
By taking cannabis completely out of the realm of criminality, that would free up enormous amounts of police and judicial resources across the country. It would also significantly improve the US’s dismal incarceration rate, especially in respect of young, male African-Americans. The arrest and conviction rates for marijuana possession are consistently higher for African-Americans in comparison to those for male, white Americans. 
Legalization would also allow for proper regulation of the drug, so it is safer for consumers to use. It also offers up a healthy stream of tax revenue. Colorado is a great example of that. Since legalizing recreational marijuana in 2012, it has brought in up to a billion dollars in tax revenue which has then be used for the collective good, such as infrastructure repairs like schools and highways. 
Another benefit of full legalization would be one of potential job-creation. The new, fully legal cannabis industry would be able to operate freely and in the open – workers would be needed for growing, cultivation and dispensing. And, of course, those workers are also another source of tax revenue as everything is being done above board.
The argument for full cannabis legalization becomes even stronger still when one considers how alcohol causes huge socio-economic and health problems countrywide, yet is fully legal in all 50 states. It is estimated that alcohol costs the American economy billions of dollars every year courtesy of health issues and crime. 
The reality is, the “pot is a gateway drug” argument that was pushed so heavily in the post-War years up until recently was nothing more than a fallacy. Just like alcohol, when used responsibly, fully regulated and legal, cannabis use is one of the hall-marks of a grown-up society.
The US really began to crack down on drug use at the turn of the twentieth century, culminating with the Reagan administration’s emphasis of the “War on Drugs” in the 1980s. While that was a war that could never be won, the “casualties” (the millions since then that have been convicted for minor cannabis possession for example) have continued to stack up remorselessly.
The US would do well to look to its northern neighbor as the way forward, with Canada fully legalizing marijuana as recently as October 2018. And guess what? Canada is still very much Canada ever since. Other countries around the world have either done the same or are considering doing the same.
Those on the right, predominantly in the Jeff Sessions-like ranks of the GOP, need to acknowledge that the War on Drugs is over and that common sense needs to now prevail when it comes to recreational (and medicinal) cannabis use. More arrests, more convictions and more stigma courtesy of minor drug-convictions that remain on record for life are simply ineffective and counter-productive.
Prohibition of alcohol was lasted a mere 13 years before the inevitability of its repeal happened. That same inevitability is the case with cannabis and the quicker that is accepted at the federal level, the better for all concerned.