US Democrats have been dealt a failure in their efforts to call witnesses at President Trump’s impeachment trial.
They needed four Republicans to vote with them to allow witness testimony, but one of the few wavering senators said he would not support the measure.
Lamar Alexander said the Democrats had proved Mr Trump acted inappropriately but it was not an impeachable offence.
The announcement paves the way for the possible acquittal of the president by the Senate as early as Friday.
The Democrats had especially wanted to call former National Security Adviser John Bolton who reportedly said Mr Trump told him directly that he was withholding US military aid to Ukraine until it agreed to investigate his rival, Joe Biden.
But the 79-year-old said: “There is no need for more evidence to prove something that has already been proven and that does not meet the United States Constitution’s high bar for an impeachable offence.”
He added: “The question then is not whether the president did it, but whether the United States Senate or the American people should decide what to do about what he did. I believe that the Constitution provides that the people should make that decision in the presidential election that begins in Iowa on Monday.”