WASHINGTON — The top Democratic investigator Dan Goldmantestified Monday that President Donald Trump’s efforts to “cheat to win an election” are a threat to national security, as the House Judiciary Committee pushes ahead with articles of impeachment.

In an acrimonious daylong hearing, Democrats outlined their case against the president, saying Trump’s push to have Ukraine investigate rival Joe Biden while withholding U.S. military aid ran counter to U.S. policy and benefited Russia as well as himself. Trump and his allies railed against the “absurd” proceedings, with Republicans defending the president as having done nothing wrong ahead of the 2020 election.

Democrats are preparing at least two articles of impeachment against Trump, likely charging him with an abuse of power and obstruction of Congress. A Judiciary committee vote could come as soon as this week.

“President Trump’s persistent and continuing effort to coerce a foreign country to help him cheat to win an election is a clear and present danger to our free and fair elections and to our national security,” said Dan Goldman, the director of investigations at the House Intelligence Committee.

Republicans rejected not only Goldman’s conclusion as he presented the Intelligence Committee’s 300-page report on the Ukraine matter, but his very appearance before the Judiciary panel. In a series of heated exchanges, they said Rep. Adam Schiff, the chairman of the Intelligence Committee, should appear rather than send his lawyer.

“Where’s Adam?” thundered Rep. Doug Collins of Georgia, the top Republican on the Judiciary Committee. “We want Schiff,” echoed Trump ally Rep. Matt Gaetz, R-Fla.

A full House vote is expected by Christmas.