There is a kingdom. During its history, the kingdom was ruled by many different regimes: absolute monarchy, constitutional monarchy, republicanism, tyrannical rule of usurpers, periods of anarchy, periods of foreign occupations, de-facto oligarchy, etc, etc. As a result, the kingdom's laws, coming from different periods of its history, have become inconsistent, overly convoluted, and overwhelmingly numerous: In many cases no one knew which law overruled which law and which law had even been validly enacted.
As a result, the kingdom's legislative and judical powers became grossly ineffective. Different forms of courts had to assemble to judge in different affairs; it wasn't clear which form was necessary in any given time. It become almost impossible to predict a court's ruling in any particular case and even worse, almost each ruling could be challenged as invalid under some obscure law. Similarily, it was unclear which body was needed to to pass any particular piece of legislation; in many cases the necessary legislative body was practically impossible to assemble ("Only King may decide in the matters of ..., but currently there is no King!") or the approprate body was considered, in practice, unable to pass any piece of legislation (for example because it required unanimity). Overlapping responsibilities of some of the bodies were not helping either. As a result, each newly passed legislation could be challenged and only contributed to the mess. This situation started to endanger the Kingdom's wellbeing, however was very profitable for legions of jurists.
Now, after years of a theoretical monarchy (with a constantly vacating throne because no one was able to claim it in such a way that couldn't be challenged and thus no one was even trying), a new sovereign finally appears... who doesn't wish to care about this convoluted legal system at all. She did have some claims to the throne, but many people had stronger claims and she could only become the Princess because some influential people saw her fit to end the chaos and placed her in power by less-than-legal means. By necessity, then, she embraces a relatively authoritarian ruling style. (Thus earning her a mocking nickname of "Empress" from her polical opponents.)
And she does attempt to fix the legal situation... in her way: She cuts the Gordian knot and orders her trusted men to start working on a brand new legal system, aimed at simplicity and consistency. Then she declares that all previous laws are now abolished and instead, only her laws are in power. This makes the Kingdom more efficient, but also leaves behind quite a few upset people: the legions of jurists who are cut from some of their income, as well as those who were interested in keeping the Kingdom paralysed.
Finally, the Empress is assassinated... and my question is, can her reform survive? The opponents of the "Empress' illegitimate new order" do have a strong argument: Even if she had been an undoubtedly valid Princess (she hadn't), she would still be unable to simply abolish all previous laws, as the Crown had not had the power over some of these laws (because of reasons outlined above). And as we know, the juridical dogma is that no law can be enacted or abolished except by means prescribed by other appropriate laws).
What would it take for her reform to survive her death? Such a reform was clearly necessary for the Kingdom's wellbeing and maybe even survival... Yet such a reform was practically impossible to be passed through 100% legal means. Given there are many people happy with the reform and many unhappy as well, what would it take for this such a reform to survive and what would it take for it to be removed from effect?
EDIT: People ask how many (powerful) people were satisfied with the reforms and how many were opposing them.
Well, the Empress did leave quite a few upset people behind, mostly those whose particular interests were in jeopardy after the reforms. With the pre-reform state of affairs and the weakness of central power bodies, certain peoples' backstage influences were allowed to flourish. The country deteriorated into a de-facto oligarchy: corrupt businessmen were allowed to do whatever they pleased, and the aristocracy was able to intrigue to no end, exercise almost absolute power in their provinces and some even were starting to think about seceding their provinces from the mainland. Unofficial power games took place of centralized power structures. Foreign spies also started gaining backstage influences.
The Empress' reforms clearly did upset many of such people. However, the Empress was able to win many of those who were tired of the chaos and who understood that the chaos was inhibiting the Kingdom's prosperity and even threatened its existence. One of such aristocrats was even responsible for plalcing her in the throne in the first place. This, in conjunction with her ability to use the Ultima Ratio Regnum, allowed her to enforce her policies... until she was assassinated. So at the moment of her death people, including powerful people, are generally split into three factions: Those who see merit in her reforms and see that these reforms allow the Kingdom to prosper, those who wish the return to old days because they miss their ability to pursue backstage and illegal interests, and those who opposed the Empress solely on the basis of her authoritarianism (this includes the legalists, who believe that law must be obeyed and must not be circumvented no matter what, not even to enact better law).