WASHINGTON — In their final appeals in President Trump’s impeachment trial, House Democrats argued on Monday that he had corrupted the presidency and would continue to put American interests at risk if the Senate failed to remove him from office. Mr. Trump’s defenders, denouncing the case against him, said he had done nothing wrong and should be judged by voters.

Making their closing arguments from the well of the Senate, the House managers and the president’s lawyers invoked history and the 2020 presidential campaign as Democrats and Republicans prepared to take the fight over Mr. Trump’s fate to the broader public arena. Neither side expected to change the outcome of the final vote on Wednesday, when the Senate is all but certain to acquit the president, largely along party lines.

The Democratic impeachment managers, led by Representative Adam B. Schiff of California, warned that Mr. Trump had tried to rig the 2020 election in his favor — by withholding military aid from Ukraine in an effort to pressure the country to investigate his political rivals — and had put a blot on the presidency that would stain those who failed to stand up to him. Calling the president “a man without character or ethical compass,” Mr. Schiff insisted that now was the time for members of his own party to choose between normalizing corruption or removing it.

“Truth matters to you. Right matters to you,” Mr. Schiff said, making a case aimed at Republicans. “You are decent. He is not who you are.”