In a statement, Cheney, a staunch conservative, said Trump was responsible for the death and destruction that day.
“The President of the United States summoned this mob, assembled the mob, and lit the flame of this attack. Everything that followed was his doing. None of this would have happened without the President,” said Cheney. “The President could have immediately and forcefully intervened to stop the violence. He did not.”
“There has never been a greater betrayal by a President of the United States of his office and his oath to the Constitution,” she added.
The House plans to vote on one article of impeachment Wednesday charging Trump with “incitement of insurrection,” as it races toward making him the first President in history to be impeached twice. Cheney has said that the vote should be driven by one’s conscience.
Unlike the other two top leaders in her conference — House Republican Leader Kevin McCarthy and House Republican Whip Steve Scalise — Cheney opposed Trump’s efforts to overturn the election, and voted to certify the results last week.
Cheney, the daughter of former Vice President Dick Cheney, has broken with Trump in the past, including on various foreign policy issues and by supporting Dr. Anthony Fauci, the nation’s leading infectious disease expert, during the coronavirus pandemic.
When asked about Cheney’s decision to impeach the President, House Speaker Nancy Pelosi responded, “Good for her to be honoring the oath of office.”
This story has been updated with additional developments Tuesday.
CNN’s Manu Raju, Phil Mattingly and Annie Grayer contributed to this report.