House Democrats concluded their arguments against President Trump on Friday by 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 impeachment managers summoned the ghosts of the Cold War and the realities of geopolitical tensions with Russia to argue that 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 allotted time ticked down, Schiff also appealed to the consciences of Republican senators weighing whether to hear from witnesses and seek more documents that Trump suppressed.

“I ask you — I implore you,” Schiff said. “Give America a fair trial. She’s worth it.”

But those same senators appeared unmoved — not just on the question of whether to acquit Trump, which they were expected to do, but also on the crucial question concerning witnesses and documents.

“We have heard plenty,” said Senator John Barrasso of Wyoming, the No. 3 Senate Republican.

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 Trump, several of them vigorously shook their heads and broke their sworn silence: “not true”.

“I hope it’s not true,” Schiff said in response.

He 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 Trump’s attempts to shut down a congressional inquiry into his actions towards Ukraine was unprecedented and undermined the very ability of the government to correct itself.

“He is a dictator,” said Representative Jerrold Nadler. “This must not stand.”