Arizona Congressman Greg Stanton says the U.S. House "has a duty" to move toward impeaching President Donald Trump.
A statement released Tuesday by the Phoenix Democrat went far beyond his prior support for an impeachment inquiry. Stanton now says that a growing "mountain of credible evidence" shows Trump has engaged in impeachable conduct.
Stanton says lawmakers took an oath to protect the Constitution, and history will judge whether they have the courage to uphold the rule of law.
Stanton is the fourth member of Arizona's Congressional delegation to join the call for an impeachment investigation. He joins fellow Democrats Raul Grijalva, Ruben Gallego and Ann Kirkpatrick.
Stanton spoke out as a growing number of Democrats call for Congress to begin an impeachment investigation. Democrats have been alarmed by a summer phone call Trump had with Ukraine's president, which came to Congress' attention through a whistleblower complaint.
Trump has insisted he's done nothing wrong.