A young man with some very big ideas about power generation and transmission, and electric light went to work for Thomas Alva Edison at Menlo park. Edison's "my way or the highway" management style rendered him not very receptive to this young man's ideas. As for the young man himself, he did not wish to remain in a place where his ideas could not be explored, and there was a row between him and Edison. So it came to pass that Nikola Tesla brought the Prophase electric motor and Generator to George Westinghouse, under whose aegis he also developed the fluorescent light bulb.
Edison had developed a thriving business selling Direct Current (DC) generators and small power distribution systems to New York's wealthy. Each installation required its own generation station because DC cannot be transmitted very far - at the voltage levels that it is useful for things like domestic lighting, it can't travel very far along copper wire.
Tesla's prophase generators, however, did not have this issue. They output three sine waves, each 120 degrees out of phase with the next corresponding to the each three windings on the armatures. Using transformers, this Alternating Current (AC) could be boosted to very high voltages at low current, which would not encounter the same amount of resistance as DC, and then stepped back down to useful voltages at the point of usage.
This gave Westinghouse a tremendous competitive advantage over Edison, especially as regarded the development of Electricity as a utility. Edison acquired a prophase generator, and the services of a sadistic electrician and set about giving demos wherein dogs were electrocuted to death to show the dangers of Alternating Current. He would describe these dogs to his audience as having been "Westinghoused."
In the meantime Tesla was also giving demos, showing the safety of Alternating Current by allowing it to be passed through his body at very high voltages and very low amperages in order to light fluorescent lamps that he held in his hand.
I leave it to readers to draw their own conclusion about the moral character of each.
While all this was going on a crazy person axe-murdered his family, gave a confession, and was sentenced to death.
Edison proposed to construct a new means of execution, called the Electric Chair. And he intended to use Alternating Current as the killing agent. Westinghouse hired an attorney to represent the condemned man and argue that since this was an untried mode of execution, it constituted cruel and unusual punishment. The case was argued before the New York Supreme Court, which allowed itself to be persuaded that death by electrocution would be painless. The US Supreme court refused to hear Westinghouse's appeal, trusting the lower courts ruling.
Even with a ruling in his favor, Edison still needed a prophase generator sufficient to the task, and Westinghouse refused to sell it to him. So Edison turned to the used market to acquire one, without disclosing to the seller what it was for.
I wonder if the Justices felt a bit hornswoggled then, when the execution had the condemned man flailing in pain for for minutes before Edison increased the power, killing him in another two. Edison went on to describe the murderer as having been "Westinghoused."
Ultimately, Alternating Current won the day, because it would be Westinghouse that would win the bid to build the hydro-electric generation station at Niagara Falls.
McKesson's case against Alabama is dissimilar from Westinghouse's case insofar as they are using a different legal theory, and accusing Alabama of Fraud. They do not sell the drug in question for use in lethal injections, so agents of the Corrections Department represented themselves as having other needs for it - on-label needs. Because the would not have sold to the DoC had they known the intended use, they were lied to, and this is fraud.
So is their action unprecedented? Insofar as legal action by a company has attempted to prevent a proprietary technology from being used to carry out an execution, probably not. And though the legal precedent set by Westinghouse's case came out in favor of the executioner, I cannot imagine that a modern court would fail to note that it relied on Edison's testimony which was proven false by subsequent events. Insofar as McKesson is not acting on behalf of the condemned, but rather bringing its own claim of fraud in its own behalf, this does differ.
There is a case that is also in the courts brought on behalf of the condemned, arguing that this sequence of execution, driven as it is by the expediency of performing the execution before the system's stock of a second necessary drug expires, is cruel and unusual.
I hope McKesson wins. My own feelings about the death penalty is that their are many crimes for which it is a just punishment, but that given the limitations of human sense and feeling, it is too easy to apply it unjustly.
An account of the Edison/Tesla rivalry may be viewed here.