You definitely have to pretend to not know about jury nullification. Don’t ever talk about it in court or with other members of the jury. You can try to persuade other jurors that the specific law that the defendent is accused of having violated is itself an unjust law. But, you cannot talk about jury nullification, which is a not guilty verdict delivered by the entire jury, based on their agreed reasoning that the law in question itself is invalid.
However, if someone reports you to the judge for attempting to persuade the jury to do that, the judge could interrogate you and use their discretion to dismiss you from the jury, declaring a mistrial, and retrying the defendent with a different jury.
You could just simply hold out and insist that the defendent is not guilty, but that will often result in a mistrial if the jury is hung – cannot reach a unanimous decision, which just leads to a retrial also.
Correct. Deliberations are secret.
However, if, during deliberations you argue based not on the evidence but solely on your disagreement with the law, other jurors may send a note to the judge stating that a juror is refusing to follow the instructions, and then, outside deliberations, in the courtroom, the judge may interrogate the jury and has the power to dismiss a holdout juror if that juror admits to ignoring the law.
To try to avoid this, one should as a juror only discuss a not guilty verdict from within the framing of reasonable doubt. It’s the better approach to never ever mention the idea or even concept of jury nullification at all ever. Not during jury selection, not during the trial, not during breaks, not during deliberations, and definitely not if speaking to the judge for any reason.
Of course a single holdout juror (or really any non-unanimous decision) will only result in a mistrial which will result in a retrial in which you will certainly not be on the jury.
IANAL