There have been a few famous feuds in science history, but there's only been one that left a scientist headless. Unfortunately for all of history, in this case, the better scientist lost. That's politics for you.
Antoine Lavoisier is considered, by some, to be the father of modern chemistry. He's one of the scientists that isolated and identified the element of oxygen. He provided evidence for the idea of conservation of mass. He predicted the existence of silicon. He might have done much more if he hadn't been killed at the age of fifty, in 1794.
Some of you have taken a look at the name "Lavoisier," and the date, "1794," and realized exactly what cut short the man's life. He was one of the victims of the famous Terror, and he was killed, publicly, by guillotine. Officially, the reason for his execution was his background as an aristocrat, and his time spent as a tax collector. Although there were plenty of corrupt tax collectors at the time - and, for that matter, corrupt aristocrats - Lavoisier was considered to be one of the few conscientious liberals among both the aristocracy and the government. He was aggressively trying to reform the tax system.
He actually got the chop, not because of his position or his work, but because he made a very bad enemy. Jean-Paul Marat was born poor, and worked his way into becoming a physician and a scientist. He applied to be accepted to the Academy of Sciences, of which Lavoisier was an exalted member. Marat was especially interested in "animal magnetism." Animal magnetism has been framed as mesmerism or hypnotism, but at the time it also encompassed the idea that certain things possessed a unique form of energy, and contraptions could be used to study that energy. Marat said that he could observe this energy, which he called "igneous fluid," leaking from heated rocks and from, no joke, the head of Benjamin Franklin. Lavoisier was unimpressed, and said so publicly. Marat was humiliated, and kept a grudge.
As Marat gained power in the revolution, he focused on Lavoisier, circulating pamphlets decrying his science, his background, and all of his activities. Marat also took up the philosophy of, "if you can't join 'em, beat 'em," leading a movement to dissolve the Academy of Science. Slowly he turned his party, and the public, against Lavoisier, just as the revolution began to get seriously dangerous. Marat's death, at the hands of Charlotte Corday, turned him for a time into a martyr. His friends and allies carried his grudge for him, arresting Lavoisier.
Lavoisier wrote to his friends, including Franklin, from prison. (I like to think that one of the letters included the phrase, "remember that nitwit who swore he could see stuff leaking from your head?") One day, political sensibilities ignited, and prisoner after prisoner was hauled from their cell, given a brief show trial, and executed. Some stories say that Lavoisier asked to be given time to finish his experiments, and was told that "The Revolution has no need for scientists." He was executed and buried in a mass grave.
A short time later public feeling turned again, and Marat was condemned while Lavoisier was exonerated. Lavoisier's widow was given his remaining possessions, and a short note admitting that he was executed under false charges. Ever since then, Lavoisier has been a symbol of the damage that politics can do to science.