I would argue that it depends on that you mean by “leaders” and “courtroom”. If by leaders we’re talking about Priests who were, presumably, concerning themselves solely with getting and keeping ritually clean in order to officiate the Passover rituals, then, yeah, just about anything they did other than that could “defile” them to some extent. That’s one of the reasons that Roman secular authorities were charged with keeping peace and order in the Temple during festivals (which Priests and Levites would normally do on normal days), because the religious authorities had to remain undefiled. Also, if by “courtroom” they mean the home of a religious leader, or, ever worse, a Roman authority — possibly even the Fortress Antonia itself — then, yes, that would also have “defiled” those Priests.

We need to remember that the Jews of Jerusalem, especially the Priests and Levites, had a very stringent CYA policy when it came to possible defilement, and that was even more the case during Festivals. (For example, dogs were completely forbidden from Jerusalem, one reasoning being that dogs are very fond of bones — as we all know — and a dog might dig up human remains and accidentally carry a human bone into the city, thus potentially defiling who knows how much of the city. That should give you an idea of how serious the religious authorities of Jerusalem were.) They were very, very, very strict about that kind of stuff, which is one of the reasons that the supposed trial of Jesus before the Sanhedrin is so far-fetched to begin with. If anything, Jesus was probably brought before Pilate and only Pilate (i.e. no Jewish authorities at all). Pilate asked Jesus a few questions about what he and his followers were up to, and, apparently, Pilate wasn’t satisfied by Jesus’ answers, and, since as a Roman Governer Pilate had the authority over life and death, Pilate simply ordered Jesus executed. It was probably just that simple. All that trial stuff we read in the Gospels is likely fiction.