From their announcement on Medium:
We are American historians devoted to studying our nation’s past who have concluded that Donald J. Trump has violated his oath to “faithfully execute the Office of President of the United States” and to “preserve, protect and defend the Constitution of the United States.” His “attempts to subvert the Constitution,” as George Mason described impeachable offenses at the Constitutional Convention in 1787, urgently and justly require his impeachment.
President Trump’s numerous and flagrant abuses of power are precisely what the Framers had in mind as grounds for impeaching and removing a president. Among those most hurtful to the Constitution have been his attempts to coerce the country of Ukraine, under attack from Russia, an adversary power to the United States, by withholding essential military assistance in exchange for the fabrication and legitimization of false information in order to advance his own re-election.
BREAKING STATEMENT: 750+ historians add their voices on #impeachment
“President Trump’s numerous and flagrant abuses of power are precisely what the Framers had in mind as grounds for impeaching and removing a president.”https://t.co/qCsP25oZ1E
— Protect Democracy (@protctdemocracy) December 17, 2019