After 15 days of testimony from 20 witnesses, the Manhattan district attorney’s office on Monday rested its case against Donald J. Trump.

The case was capped by three days of grinding cross-examination of his former fixer, Michael D. Cohen, who finally stepped off the stand on Monday afternoon, leaving jurors to weigh the truthfulness of the prosecution’s star witness.

The defense began its case on a mission to sully his credibility, but the second witness Mr. Trump’s lawyers called to the stand quickly became embroiled in a squabble with the judge, Juan M. Merchan. The judge, not surprisingly, prevailed.

Though the defense is expected to be brief, Justice Merchan said that closing arguments would not happen until next week.

The former president is charged with falsifying 34 business records related to the reimbursement of the $130,000 hush-money payment to a porn star, Stormy Daniels, who says she had sex with Mr. Trump in Lake Tahoe, Nev., in 2006. Mr. Trump, 77, has denied the charges and that he had an encounter with Ms. Daniels. If convicted, he could face prison or probation.

Here are five takeaways from Mr. Trump’s 19th day on trial.

‘The defense calls Robert Costello.’ It didn’t go well.

After Mr. Cohen was done, the defense commenced. After brief testimony from a paralegal about phone records, the defense called Robert Costello, a former legal adviser to Mr. Cohen, who said they spoke in 2018 and that Mr. Cohen told him that Mr. Trump “knew nothing” about payments to Ms. Daniels.