Judge’s Instructions Will Be a Road Map for Jury Weighing Trump’s Fate

Within about an hour, a Manhattan jury will begin a discussion of historic import: determining whether Donald J. Trump is guilty of 34 felonies.

But before the jurors begin to deliberate, the judge, Juan M. Merchan, will deliver legal instructions that will help guide the 12 New Yorkers who will hash out Mr. Trump’s fate.

Justice Merchan will describe the legal meaning of the word “intent” and the concept of the presumption of innocence. He will remind the jurors that they pledged to set any biases aside against the former president before they were sworn in, and that Mr. Trump’s decision not to testify cannot be held against him.

Then, according to a person with knowledge of the instructions that Justice Merchan plans to deliver, he will explain the 34 charges of falsifying business records that Mr. Trump faces. It will likely be the most important guidance that the judge offers during the trial. And it is no simple task.

In New York, falsifying records is a misdemeanor, unless the documents were faked to hide another crime. The other crime, prosecutors say, was Mr. Trump’s 2016 violation of state election law that prohibited conspiring to aid a political campaign using “unlawful means.”

Those means, prosecutors argue, could include any of a menu of other crimes. And so each individual false-records charge that Mr. Trump faces contains within it multiple possible crimes that jurors must strive to understand.