(1) The MPC is perhaps the last gasp of the failed American dream of a common law. An organization called the American Legal Institute tried to create a common criminal code that could be used across the country by both States and the federal government. Although it had a good deal of momentum in the 1960's and 70's, in the end 13 States and, most importantly, the federal government rejected the MPC in its entirety. Most spectacularly, Idaho adopted the MPC and within two months the Idaho legislature ripped up the new laws and went back to its own criminal laws. In most States which adopted it the legislatures picked and chose which parts they would use and there are few States you can find commonly listed as having adopted it almost entirely; usually I see New York, New Jersey, and Oregon. Even then, flaws in the MPC, such as its failure to deal with drug offenses in any manner, left the most slavishly loyal States on their own in dealing with these crimes. Furthermore, as decades have passed various legislatures have continued to modify their State's version of the MPC
1 independent of each other and the laws of each have moved further away from the common law aspiration behind the MPC.
(2) Times do not seem ripe for another attempt. In part this is because in the modern era the ALI, much like the ABA, has become more and more overtly an advocacy group undertaking efforts to eliminate the death penalty and, most recently, trying to water down sex offender registration (some might say drown). It has gotten to the point that there have been calls for judges to not associate themselves with the organization. To be fair, the ALI's MPC was never not advocating for positions that weren't part of most State's criminal laws. In fact, its imposition of its writers' moral values was present from the beginning. It ignored the moral crimes found in most every State's laws (mostly based on sexual mores of the time which went back legally to 1533) and toughened gun control laws2. It never claimed the MPC was a "restatement" like it does for areas of law such as torts. (a) The MPC's strengths were that it cleaned out the detritus of existing criminal law, which was based largely on a jumble of judicial precedent combined with statutory interventions from the various legislatures, and replaced them with a better organized, more easily accessible code. This same could have been accomplished with a restatement - basically a much distilled version of criminal laws as found in treatises like Corpus Juris Secundum and/or its predecessor. (b) It was a choice to put forth a set of statutes which its authors saw as morally forward looking. It's not hard to see why legislatures would be drawn by the siren song of (a) even if it came with the baggage of (b) - which many did their best to excise. The modern problem seems to be that the ALI has lost the pragmatism of an organization offering a strong value added prospect to the legislatures while it has leaned into pushing the adoption of its moral positions of the moment.
(3) The ALI's attempt to create one common law across the United States has failed and is further fraying. Moreover, a revised attempt by the ALI to create one common criminal code across the country would almost surely fail. Current conditions aren't nearly the same and, having fallen farther into the pit of morality advocacy, the ALI has lost much of its universal respect. Sure, it's still loved by academics, but its appeal is muted in legislatures. The States interested in cleaning up their criminal law and adopting a code did so back in the 60's and 70's. Once these States adopted codes, the strongest point in the MPC's favor was fulfilled. There's far less incentive to go back in and do another rehash because someone wants a legislature to change laws to conform with their moral perspective once a code has already been adopted that makes criminal law simpler and more pragmatic.3
(4) Can a nationwide criminal code be developed in the United States? No. Not really. Even assuming you could get the federal government (the big get) and every single one of the 50 States to adopt the exact same code, the very next time the legislatures met they would all come up with new and different laws to add and the fraying would begin again. Could the MPC have been more successful?4 Probably. That would have required something more along the lines of a Code Restating Criminal Law which started with federal law, perhaps reorganizing and simplifying it, and then filled in the gaps left from laws which a majority of States either recognized through their statues or case law.
If this approach had been used instead of the MPC approach, a Code Restating Penal Law (CRPL) would be relevant even in those jurisdictions which had not adopted the Restatement. As things are today, the ALI's effort stands irrelevant in California, Idaho, Maryland, Massachusetts, Michigan, Mississippi, Nevada, North Carolina, Oklahoma, Rhode Island, South Carolina, Vermont, West Virginia, Louisiana, and to federal criminal law (and, in my experience, Virginia although there are consistent claims Virginia has adopted some of it). If the ALI had taken this approach, the fact that South Carolina didn't adopt its code wouldn't mean that the CRPL's commentary and case law developed in CRPL States would be useless. By gambling for all, the ALI excluded itself from some. Whether that was a good or bad approach is a matter of opinion.
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1 "[W]hen the MPC reform movement conflicted with the tough-on-crime movement, it was, unsurprisingly, the MPC’s reform efforts—the efforts of legal professionals and academics more than politicians—that lost." [unsurprising because we live in a democratic republic, not an oligarchy]
See a more thought through explanation: Can a Model Penal Code Second Save the States from Themselves, page 170 (The Degradation Problem)
2 For instance:
§ 5.06(2): If a person possesses a firearm or other weapon on or about his person,in a vehicle occupied by him, or otherwise readily available for use, it is presumed that he had the purpose to employ it criminally, unless:(a) the weapon is possessed in the actor's home or place of business;(b) the actor is licensed or otherwise authorized by law to possess such weapon; or (c) the weapon is of a type commonly used in lawful sport. [no mens rea and assumes licensing]
3 I've tried to finds a news article or anything else on the internet that
shows the adoption of any of the new "revisions" that the ALI is making
to the MPC which do not reflect the statutes developed by the various
states. There must be some state somewhere doing it. Otherwise the ALI
is just putting things out there to show how out of touch and irrelevant
it currently is. I just haven't found them. If anyone can point me to an article or paper, I would appreciate it.
4 Yes, I know the MPC has been adopted in 35 to 37 States (depending upon which article I'm reading). This is successful, but the MPC never got over the summit. Some fairly important States rejected it (California, Michigan, North Carolina) and I know at least one other listed as adopting part of the MPC, Virginia, doesn't seem to have very much of it. I know I'm still using common law definitions of trespass, larceny, robbery, etc. derived mostly from judicial sources. The biggest failure was the inability to get it adopted by Congress as federal law which guaranteed semi-failure.