Hundreds of law professors from schools across the country published an open letter Friday declaring President Donald Trump's conduct involving Ukraine as "clearly impeachable," an assertion that comes after a daylong hearing earlier this week at which Republicans and Democrats sharply divided over their assessment of the president's actions.

The letter, posted on the website Medium and sponsored by the government watchdog Protect Democracy, had been signed by 520 professors as of Friday afternoon. The assertions were an attempt to frame the debate as one of law, and not partisan politics.

"There is overwhelming evidence that President Trump betrayed his oath of office by seeking to use presidential power to pressure a foreign government to help him distort an American election, for his personal and political benefit, at the direct expense of national security interests as determined by Congress," the professors said in the letter. "His conduct is precisely the type of threat to our democracy that the founders feared when they included the remedy of impeachment in the Constitution."

Professors signed the letter from a variety of law schools across the country, including Columbia Law; Yale; Stanford; Harvard; Duke; Emory University; Georgetown Law; Berkeley Law; University of Florida; University of Pennsylvania; Albany Law; University of Texas; Rutgers; and the University of Georgia.

The House impeachment investigation focuses on claims Trump abused the power of the presidency to pressure Ukraine to meddle in U.S. politics to the president's benefit. The Trump administration withheld nearly $400 million in military aid from Ukraine as the president asked for a "favor" from the country to investigate Democratic presidential contender Joe Biden and his son Hunter.

Trump has denied he put any untoward or unlawful pressure on Ukraine to meddle in U.S. political affairs. Trump's allies have argued he was concerned about corruption in Ukraine, and that military aide to the U.S. ally was delivered, in the end, without any promise from Ukrainian leaders to investigate the Bidens. Many Republicans have raised questions that point to Ukraine, and not Russia, as having orchestrated the 2016 presidential election interference campaign.

At last Wednesday's impeachment hearing in the House Judiciary Committee, the Republican-named witness, Jonathan Turley, a professor at George Washington University School of Law, said a proven quid pro quo involving Trump and Ukraine could be impeachable. But he alleged the evidence is not there to make such a conclusion.

"This is a process that must focus on impeachable conduct, not imprudent or even obnoxious conduct," Turley said in his prepared testimony.

The letter-signers did not take a position on whether Trump should be impeached and removed for his conduct, saying ultimately that's a question for House and Senate members.

"If the House of Representatives impeached the President for the conduct described here and the Senate voted to remove him, they would be acting well within their constitutional powers," the professors wrote. "Whether President Trump's conduct is classified as bribery, as a high crime or misdemeanor, or as both, it is clearly impeachable under our Constitution."

House Democrats are drafting articles of impeachment, and scheduled a hearing for Monday at which counsels for the House intelligence and judiciary committees will present evidence purporting to support impeaching Trump. White House Counsel Pat Cipollone faces a 5 p.m. deadline today to say whether and how the president might participate in House proceedings.