I have jury duty this week. Maybe. it looks like I will have to go in, but don't know if I'll get selected. But my aim is to try to get on, and if I can then probably do the Null-word without ever saying the Null-word. I do have a few questions for anyone who might know about this stuff. This is in the US.
First off, I have been on a jury before and it ended in a hung jury result and I do take credit for some praxis there even though it was a long time ago before I fully knew what that word meant. Anyway, several people who I told I was previously on a hung jury have told me that means I can't be on a jury again, but I don't know if they know what they're talking about. Is it true? Am I disqualified? If so, do I even have to report that fact?
The trial I was a juror for last time was over 15 years ago, so there are some things I don't remember well and other things that have probably changed since then. Like will it be on a questionnaire where they ask if I've been on a jury before and what the result was? I know they ask some questions vocally in person if you're being considered for selection, so is it only then that they ask about history as a juror? I assume in either case, I'd be at risk of perjuring myself if I "forgot" and wrote/said "no" for that question? Or maybe they even like it when someone has been on a jury before, just not for a hung jury, and I could leave off that particular detail?
If my well hung history isn't a deal breaker for whatever reason, what else should I know about so that I would be more likely to be selected? I'd guess a lot of it is context dependent.
This next question is a whole other topic really but I've been wondering about this site's thoughts on it even before getting the summons. As an ML on a jury within a capitalist penal system, would you say there's an obligation by principle to always nullify? It seems like edge cases must exist, even if it is playing into the bourgeois system. For example, a case where there is abuse of a child and it appears clearly evident that the defendant is guilty. I realize the system set to "rehabilitate" this person is not even "broken" but functions to punish the working class and facilitate legalized slavery, while benefiting and protecting the ruling class. It is still better to do what's necessary to help prevent more abuse by this individual from occurring, and go for conviction in that very specific case. Right? Another kind of edge case might be one where every once in a while, very rarely maybe that blue wall cracked just a little, and the defendant is actually a cop on trial for doing usual cop shit, but did it too openly or something. In that kind of one in a million case the obligation is to do everything possible to convict the bastard, I'm sure.
and 
Thank you, this is good information to know. They never asked me or anyone else being selected if there was intent to do nullification, not even in lawyer-speak, so I wasn't expecting they would this time either. I figured if they're at the point of asking you that, then they've already decided they're not going to choose you to be on the jury.
As far as not treating it as a hard rule to always prevent conviction in all cases, I completely agree with everything you said. My question about that was not so much to ask what the "right" answer was, as I already firmly believe that there are cases where going by the rulebook and convicting someone is undeniably the right thing to do. The question was more a curiosity about the opinions of commenters here. I would hope most would be in agreement, but consensus around here on that sort of thing has surprised me before.