A former Republican senator is urging members of his party to call for witnesses as part of President TrumpDonald John TrumpDemocrats outraged over White House lawyer’s claim that some foreign involvement in elections is acceptableSenators take reins of impeachment trial in marathon question sessionWhite House announces task force to monitor coronavirusMOREs impeachment trial. 

Former Sen. John Warner (Va.) asked Republicans to honor the nation’s history of judicial norms as the impeachment process continues, largely echoing many Democrats that have been calling for witnesses since the start of the impeachment trial. 

As a lifelong Republican and a retired member of the U.S. Senate, who once served as a juror in a Presidential impeachment trial, I am mindful of the difficult responsibilities those currently serving now shoulder, Warner said in a statement, shared by a New York Times reporter on Twitter Thursday. 

NEW: Former Senator John Warner, a Republican and elder statesman of Virginia politics, has issued a statement calling on fellow Republicans to follow judicial norms by welcoming relevant witnesses and documents in President Trumps impeachment trial. pic.twitter.com/GeRRjIkHfo

Sheryl Gay Stolberg (@SherylNYT) January 31, 2020

I believe, as I am sure you do, that not only is the President on trial, but in many ways so is the Senate itself. As such, I am strongly supportive of the efforts of my former Republican senate colleagues who are considering that the Senate accept the introduction of additional evidence that they deem relevant, he added. 

Warner said that throughout U.S. history, judicial systems have largely supported the judicial norms of evidence, witnesses and relevant documents. 

I respectfully urge the Senate to be guided by the rules of evidence and follow our nations judicial norms, precedents and institutions to uphold the constitution and the rule of law by welcoming relevant witnesses and documents as part of this impeachment trial, he said. 

A vote on whether or not to allow witnesses will be held on Friday. Democrats need at least four Republicans to join them to pass the measure. 

Although some GOP senators have signaled they are open to hearing from witnesses, Republicans voiced confidence Tuesday that they will be able to block witnesses. 

Democrats have been pushing to hear from first-hand witnesses of Trumps decision making with regard to Ukraine. Their push was bolstered after The New York Times reported Sunday that former national security advisor John BoltonJohn BoltonSenators take reins of impeachment trial in marathon question sessionDemocratic senator to force vote requiring Roberts to weigh in on witnessesOvernight Defense: Bolton, GOP senators see close ties challenged | Republicans fume over Dem maneuver on Iran bills |Trump criticizes Democrats over war powers vote MORE claims in a manuscript of his forthcoming memoir that Trump tied Ukrainian aid to investigations into his political opponent, Joe BidenJoe BidenSenators take reins of impeachment trial in marathon question sessionSanders campaign says it raised more than .3 million in one day after negative ad Warren’s dog campaigns in Iowa while senator sits in impeachment trialMORE. 

Bolton has said he would testify if subpoenaed.