Jurors in Donald J. Trump’s criminal trial will begin deliberations on Wednesday after hearing hours of closing arguments that portrayed the case in stark and irreconcilable terms.

It could take hours, days or even weeks for the 12 New Yorkers to reach a verdict in the first criminal trial of an American president. And before they begin deliberating, the jurors will receive instructions from the judge on the relevant law.

This last stage of the weekslong case comes a day after the jurors watched both sides deliver their final flurry of arguments.

A prosecutor, Joshua Steinglass, meticulously described a scheme on the eve of the 2016 election to muzzle a porn star’s account of a sexual encounter with Mr. Trump. The woman, Stormy Daniels, kept quiet after Mr. Trump’s onetime fixer, Michael D. Cohen, bought her silence with a $130,000 hush-money deal.

The machinations crossed a legal line, prosecutors say, when Mr. Trump reimbursed Mr. Cohen for the hush money and falsified records to cover the whole thing up.

“All roads lead to the man who benefited the most, Donald Trump,” Mr. Steinglass said, adding that it was done to “hoodwink the American voter.”

A defense lawyer, Todd Blanche, said in his summation that Mr. Trump’s actions were not crimes, but merely business as it is commonly practiced. The felony charges of falsifying business records, he said, were a lie-riddled sham without “a shred of evidence.”

Mr. Blanche spent much of his closing argument attacking the credibility of Mr. Cohen, calling him “the greatest liar of all time” and urging the jury to reach “a very quick and easy not guilty verdict.”

Here’s what to know about the first prosecution of an American president:

• Mr. Trump is charged with 34 felony counts of falsifying business records, which prosecutors say Mr. Trump used to disguise the repayment to Mr. Cohen as ordinary legal fees. If convicted, he faces probation or up to four years in prison. Mr. Trump has denied wrongdoing and says he never had sex with Ms. Daniels, who took the stand and described an encounter with him after a golf tournament in Lake Tahoe, Nev., in 2006. Here’s a refresher on the case.

• In Mr. Steinglass’s closing argument, he told a sweeping story about a fraud on voters. He argued that an agreement Mr. Trump struck with The National Enquirer to buy and bury unflattering stories was a “subversion of democracy” that prevented the American people from deciding for themselves whether they cared that Mr. Trump had sex with a porn star or not. His arguments could be crucial: Prosecutors needed to show that the business records were falsified to hide a conspiracy to influence the 2016 election.

• Mr. Blanche assailed Mr. Cohen, casting him as a rogue actor and a liar bent on revenge. He argued that there was nothing false about the documents, because Mr. Cohen had in fact performed legal work — and suggested that Mr. Trump had little reason to pay attention to them in any case, because he was the “leader of the free world” at the time.