Graham Platner withdrew from the Maine Senate race on Friday, ending his tumultuous political saga and allowing Democrats to begin the process of selecting an alternate nominee.

“I write to formally withdraw my candidacy for the United States Senate,” Mr. Platner wrote in a letter to the Maine secretary of state. “Please consider this notice as my official withdrawal from consideration for office.”

Mr. Platner’s official departure from the race, which was confirmed by Jana Spaulding, an aide to the Maine secretary of state, comes two days after he announced he would suspend his campaign following an accusation of rape, which he denied. It comes as Maine Democrats have begun conversations about how they will build a process to replace him, which is expected to cumulate in a state convention in two weeks.

Tim Balkcontributed reporting.