Paladin

paladin [PAL-uh-din]
n. any knightly or heroic champion; any determined advocate or defender of a noble cause

[Derives from Latin palātīnus ("imperial functionary"), originally taken from Palātium Hill in Rome]

Before I get into the usage of paladin, let me digress a moment on Palātium (aka Palatine), its original root word/name. Palatine is the name of one of the Seven Hills of ancient Rome, where aristocrats (and later the emperor) built large homes. The emperor's house was known thereafter as his palace.

When Pompey captured Jerusalem in 63 BCE, the Romans conquerors renamed all of ancient Israel and Judaea Palatine (or Palestine) after the famous hill in Rome.

Palātium has spawned a few other related English words: palatine ("having royal privileges"), palatial ("suitable for a palace; stately; magnificent") and palace ("the official residence of a king, queen, etc."). The similarly spelled palate ("the roof of the mouth; the sense of taste") and palatable ("good-tasting") don't come to English from Palātium. They come from the Latin palātum ("the roof of the mouth").

To understand how paladin came to be synonymous with hero, you need to know that the circle of tweleve men (that is, the palace officials) around Charlemagne were that Frankish emperor/king's palaisins or palatins (paladinos in Italian, which became paladins in English). Much like King Arthur's fabled Knights of the Round Table, the paladins of Charlemagne (supposedly) fought on his behalf. Among other things, Charlemagne is famous for spreading Christianity (by force), defeating the pagan Saxons and the Muslim Saracens. In Christian literature (largely written in Italian) which sprang up after Charlemagne died in 814, the paladins are prominently featured in epic romances, saving chaste women and doing any number of heroic acts for the sake of good. It is significant that there were twelve paladins and one king, as a parallel to Jesus and his twelve apostles in Christian mythology.

In the Oxford Companion to the Supreme Court, Stanley Kutler describes the Court as a hero, in the case New York Times Co. vs The United States, in which the Court ruled that the government could not restrain the Times or any other paper from publishing the Pentagon Papers, which had been illegally given to them by Daniel Ellsberg, a former official in the Defense Department who worked on a part of the Papers:

The Supreme Court's decision legitimated the media's assaults against governmental secrecy and its self-assumed status as the people's paladin against official wrongdoing.