WASHINGTON — The House impeachment managers concluded their arguments against President Trump on Friday with a forceful plea for the Senate to call witnesses, while portraying his pressure campaign on Ukraine as part of a dangerous pattern of Russian appeasement that demanded his removal from office.
Ending their three-day presentation in the Senate, the president’s Democratic prosecutors summoned the ghosts of the Cold War and the realities of geopolitical tensions with Russia to argue that Mr. Trump’s abuse of power had slowly shredded delicate foreign alliances to suit his own interests.
“This is Trump first, not America first, not American ideals first,” said Representative Adam B. Schiff of California, the lead House manager. “And the result has been, and will continue to be, grave harm to our nation if this chamber does not stand up and say this is wrong.”
Hours later, as his time ticked down, Mr. Schiff sought to appeal to the consciences of Republican senators weighing whether to hear from witnesses and seek more documents that Mr. Trump suppressed from House investigators.
“I ask you — I implore you,” Mr. Schiff said. “Give America a fair trial. She’s worth it.”
But at one point, Mr. Schiff’s fiery final oration appeared to alienate the very Republicans he was trying to win over. When he referred to an anonymously sourced news report that Republican senators had been warned that their heads would be “on a pike” if they voted against Mr. Trump, several of them vigorously shook their heads and broke the trial’s sworn silence to say “not true.”
“I hope it’s not true,” Mr. Schiff responded, pressing his point.
Mr. Schiff and the six other managers prosecuting the president spent much of Friday tying up the facts of the second charge, obstruction of Congress, and arguing that Mr. Trump’s attempts to shut down a congressional inquiry into his actions toward Ukraine was unprecedented and undermined the very ability of the government to correct itself.
“He is a dictator,” said Representative Jerrold Nadler of New York. “This must not stand.”
But even as the managers pulled together their complex case, the Republican-controlled Senate appeared unmoved — not just on the question of whether to acquit Mr. Trump, which it is expected to do, but also on the crucial question of compelling witnesses and documents that the president has suppressed.
“We have heard plenty,” said Senator John Barrasso of Wyoming, the No. 3 Senate Republican.
He said that many in his party had quickly soured on the soaring appeals by House Democrats to repudiate Mr. Trump’s behavior. As day turned to evening on the fourth full day of the trial, many senators unaccustomed to long hours in the Capitol appeared to have simply been numbed by the House managers, and were anticipating the president’s defense, set to begin Saturday.
They were presented with three days of often vivid narrative and painstaking legal arguments that Mr. Trump sought foreign interference in the 2020 election on his own behalf, by using vital military aid and a White House meeting as leverage to pressure Ukraine to investigate his political rivals. Yet the pool of moderate Republican senators that had expressed openness to joining Democrats in insisting on witnesses or new documents appeared to be dwindling, not growing.
Comments by Senators Lamar Alexander of Tennessee and Lisa Murkowski of Alaska suggested that they may have cooled to the idea, although Senators Susan Collins of Maine and Mitt Romney of Utah gave no indication that they had shifted.
Still, Ms. Collins was among those shaking her head when Mr. Schiff referred to the purported threat against Republican defectors, as he portrayed Mr. Trump as a tyrant bent on intimidating would-be critics.
“‘Head on a pike,’ that’s where he lost me,” Ms. Murkowski said afterward, clarifying that she meant in the speech, not necessarily on votes for witnesses. “I thought he did fine until he overreached.”
Throughout Friday, inside and outside the chamber, the House managers and Democratic senators worked in tandem to appeal to their consciences, hinting strongly at the political stakes if they failed to press for a more thorough airing of the charges against the president.
“We’ve made the argument forcefully, the American people have made the argument forcefully that they want the truth,” said Senator Chuck Schumer of New York, the Democratic leader. “Will four Republican senators — just four — rise to the occasion, do their duty to the Constitution, to their country to seek the truth?”
They got an unexpected lift early in the day when a 2018 recording surfaced of Mr. Trump appearing to order the firing of Marie L. Yovanovitch, then the United States ambassador to Ukraine. The recording was first reported by ABC News and later handed over to the House by Lev Parnas, an associate of Rudolph W. Giuliani, the president’s personal lawyer.
The recording appeared to confirm earlier claims by Mr. Parnas that he had told Mr. Trump about rumors that Ms. Yovanovitch was not loyal to him. The House’s impeachment inquiry concluded that the ambassador was ultimately removed in 2019 as part of Mr. Trump’s attempt to strong-arm Ukraine to announce investigations of his political adversaries.
“Get rid of her,” Mr. Trump can be heard to say, according to ABC. “Get her out tomorrow. I don’t care.”
Without an agreement to take new testimony or subpoena documents relevant to the case, Mr. Trump may be headed toward a historically speedy acquittal in as little as a week from now, before the Iowa caucuses or his planned State of the Union address. That would make the third impeachment trial of a president in American history the shortest.
Mr. Trump’s defense team plans to open its arguments on Saturday, though senators were expected to meet for only an abbreviated, two- to three-hour session before adjourning the trial until Monday afternoon.
Mr. Trump was not pleased about the schedule, writing Friday morning on Twitter that his team had been “forced” to start on a Saturday, a time “called Death Valley in T.V.” He also turned around Democrats’ accusation, declaring that “the Impeachment Hoax is interfering with the 2020 Election,” not him.
Jay Sekulow, one of Mr. Trump’s lawyers, said his team would treat the weekend session like a “trailer,” providing an overview of their case for acquittal while holding back until Monday the president’s more television-friendly lawyers, the former independent counsel Ken Starr and Alan Dershowitz.
Democrats used almost every one of the 24 hours afforded to them by senators to make their case, determined to persuade American voters watching at home who will cast ballots in just 10 months, if not senators.
On Wednesday, Mr. Schiff and each of the managers took turns introducing the facts of the case in narrative form, unfolding the tale of Mr. Trump’s alleged misconduct chapter by chapter. Beginning with the abrupt removal of Ms. Yovanovitch, they said that Mr. Trump empowered first Mr. Giuliani and then American officials to push Ukraine to announce investigations of former Vice President Joseph R. Biden Jr. and other Democrats, before himself asking that country’s leader to “do us a favor.”
When the Ukrainians resisted, they added, he withheld a coveted White House meeting and almost $400 million in military aid the fledgling democracy badly needed to fend off a menacing Russia. And when Congress found out, he undertook an across-the-board campaign to block officials from testifying or producing records that would reveal the scheme.
On Thursday, Mr. Nadler lectured extensively on the constitutional and historical standards for impeachment, setting the stage for the managers to methodically argue that Mr. Trump’s actions toward Ukraine constituted an impeachable abuse of power that warrants his removal from office.
Mr. Schiff completed that case on Friday, directly engaging the national security implications of Mr. Trump’s actions as he argued that the president was a serial offender in seeking foreign help for his own political benefit, allowing himself to be used as a tool of Moscow’s agenda in the process. As a candidate, Mr. Trump welcomed Russia’s interference in the 2016 election to help him win the White House, Mr. Schiff noted, and then as president, he repeatedly cast doubt on the conclusions of American intelligence agencies about that interference. Later, Mr. Trump said outright that he would welcome foreign campaign assistance again.
The California Democrat played a video of the news conference in Helsinki, Finland, where Mr. Trump stood next to President Vladimir V. Putin of Russia and accepted his denial that Moscow meddled in the 2016 election.
“That’s one hell of a Russian intelligence coup,” Mr. Schiff said. “They got the president of the United States to provide cover for their own interference with our election.”
At another point, Mr. Schiff showed a clip of Senator John McCain, Republican of Arizona, who was an outspoken champion of Ukraine and Russia hawk, promoting the benefits of bipartisan American support for Kyiv to contain Russia and its anti-democratic agenda.
The move appeared to be a subtle effort to appeal to Republican senators, many of whom respected Mr. McCain and share his strongly anti-Russia stance, to place those values above their loyalty to the president.
As the managers moved on to the obstruction of Congress charge, they contended that Mr. Trump’s blockade of evidence was far more pernicious than the kind of partisan squabbles that are typical between Congress and the White House.
Even Presidents Bill Clinton and Richard M. Nixon, they said, had produced documents to the investigations that would threaten them with impeachment. Mr. Trump’s administration had not handed over a single page, declaring for the first time an across the board objection to House subpoenas.
Trying to head off Mr. Trump’s defense team, which argues that the president was lawfully protecting the interests of the executive branch from a politically motivated House, the managers pointed out that he never actually invoked executive privilege, the legal mechanism afforded to presidents.
“Only one person in the world has the power to issue an order to the entire executive branch,” said Representatives Val B. Demings, Democrat of Florida. “And President Trump used that power not to faithfully execute the law, but to order agencies and employees of the executive branch to conceal evidence of his misconduct.”
Reporting was contributed by Maggie Haberman, Carl Hulse, Catie Edmondson, Michael D. Shear and Emily Cochrane.