Judge Merchan told the jury that they have the ultimate authority in determining the truthfulness of a witness' testimony -- an instruction that might come in handy given the emphasis that defense lawyers placed on Michael Cohen's testimony, which they say includes lies.
"You will alone determine the truthfully and the accuracy of the testimony of each witness," Merchan said.
He added that the jury could either disregard the testimony of an untruthful witness entirely, or disregard part of it.
"There is no particular formula" to determine credibility, Merchan said.
"You may consider whether the witness has any interest in the outcome of the case," he said -- another matter that might weigh on jurors' minds.
"You may consider whether a witness did have, or did not have, a motive to lie," the judge said.
Trump's attorney had told the jury Cohen had an "axe to grind" against his former boss. Prosecutors partially conceded that Cohen had a motive, acknowledging that, to date, he is the only one who suffered any consequences from the matter at hand.
Trump, at the defense table, appeared to look over to the jury and offer a bit of a closed-mouth grin.